Chapter 14

(J. F. St.)

1The fact that the father-in-law of Moses is called Reuel in v. 18, as contrasted with the name Jethro, which occurs in iii. 1 f. and in all subsequent passages from E, cannot be taken as conclusive on this point, since critics are agreed that “Reuel” in this verse is a later addition: had it been original we should have expected the name to be given at v. 16 rather than at v. 18. But, if no argument can be based on the discrepancy between the two names, we may at least assume that the namelessness of the priest in v. 16 f. points to a different source for those verses from that of iii. 1 f. Elsewhere J speaks of “Hobab, the son of Reuel the Midianite, Moses’ father-in-law” (Num. x. 29); the addition, “the priest of Midian,” only occurs in the (secondary) passages iii. 1, xviii. 1 (E). Probably RJE omitted the name in ii. 16 and added “the priest of Midian” in iii. 1, xviii 1, from harmonizing motives. Further, vv. 15B-22 speak ofoneson being born to Moses at this period, a statement which is borne out by iv. 20, 25 (“sons” in iv. 20 is obviously a correction), whereas ch. xviii. (E) mentionstwosons.The original order of events in J seems to have been as follows: after the death of Pharaoh (ii. 23a; the Septuagint repeats this notice before iv. 19) Moses returns to Egypt with his wife and son (iv. 19, 20) in obedience to Yahweh’s command. On the way he is seized with a sudden illness, which Zipporah attributes to the fact that he has not been circumcised and seeks to avert by circumcising her son (iv. 24-26). The scene of the theophany, therefore, according to J, is to be placed on the way from Midian to Goshen. Probably the displacement of iv. 19, 20, 24-26 is due to the editor of JE, who was thus enabled to combine the two narratives of the theophany.2Cf. iv. 30; Aaron had received no command to do the signs, and the words “and he did the signs” are most naturally referred to Moses.3The expansion in iii. 8c, 15, 17b; iv. 22, 23, are probably the work of a Deuteronomistic redactor.4The genealogy of Moses and Aaron (vv. 14-27) appears to be a later addition.5Unless we follow Riedel and read simply “and worshipped” (וישתחוו) instead of “and drank” (וישתו), treating “and ate” (ויאכלו) as a later addition; cf. HDB, extra vol. p. 631 note.6Vv. 6-9 are out of place here: they belong to the story of Moses’ intercession in ch. xxxiii.7This view is confirmed by (a) a comparison of v. lb (“and I will write”) with vv. 27, 28; according to the latter,Moseswrote the words of the covenant; and (b) the tardy mention of Moses in 4b; the name would naturally be given at the beginning of the verse.8Others suppose that the present position of ch. xxxiv. is due, in the first instance, to RJE, but in view of the other Deuteronomic expansions in vv. 10b-16, 23, 24, it is more probable that J’s version was discarded by RJE in favour of E’s, and was afterwards restored by RD.9Reading “the sacrifice of my feasts” for “the sacrifice of the feast of the Passover.”10Unless, with Bacon, we are to regard xxiv. 12-14, 18b as original. More probably a later editor has worked up old material of E (of which there are unmistakable traces) in order to include the whole of xx.-xxiii. in the covenant: xxiv. 15-18a are an addition from P.11The present text of xxiv. 12 also has probably been transposed in accordance with the view that the “judgment” formed part of the covenant, cf. Deut. v. 31. Originally the latter part of the verse must have run, “That I may give thee the tables of stone which I have written, and may teach thee the law and the commandment.” For further details see Bacon,Triple Tradition of Exodus, pp. 111 f., 132 f.12According to Deut. x. 1 f., which is in the main averbalexcerpt from Ex. xxxiv. 1 f., Yahweh ordered Moses to make an ark of acacia woodbeforehe ascended the mountain.13To the same hand are to be ascribed also xxvii. 6, 20, 21; xxviii. 41; xxix. 21, 38-41.

The original order of events in J seems to have been as follows: after the death of Pharaoh (ii. 23a; the Septuagint repeats this notice before iv. 19) Moses returns to Egypt with his wife and son (iv. 19, 20) in obedience to Yahweh’s command. On the way he is seized with a sudden illness, which Zipporah attributes to the fact that he has not been circumcised and seeks to avert by circumcising her son (iv. 24-26). The scene of the theophany, therefore, according to J, is to be placed on the way from Midian to Goshen. Probably the displacement of iv. 19, 20, 24-26 is due to the editor of JE, who was thus enabled to combine the two narratives of the theophany.

2Cf. iv. 30; Aaron had received no command to do the signs, and the words “and he did the signs” are most naturally referred to Moses.

3The expansion in iii. 8c, 15, 17b; iv. 22, 23, are probably the work of a Deuteronomistic redactor.

4The genealogy of Moses and Aaron (vv. 14-27) appears to be a later addition.

5Unless we follow Riedel and read simply “and worshipped” (וישתחוו) instead of “and drank” (וישתו), treating “and ate” (ויאכלו) as a later addition; cf. HDB, extra vol. p. 631 note.

6Vv. 6-9 are out of place here: they belong to the story of Moses’ intercession in ch. xxxiii.

7This view is confirmed by (a) a comparison of v. lb (“and I will write”) with vv. 27, 28; according to the latter,Moseswrote the words of the covenant; and (b) the tardy mention of Moses in 4b; the name would naturally be given at the beginning of the verse.

8Others suppose that the present position of ch. xxxiv. is due, in the first instance, to RJE, but in view of the other Deuteronomic expansions in vv. 10b-16, 23, 24, it is more probable that J’s version was discarded by RJE in favour of E’s, and was afterwards restored by RD.

9Reading “the sacrifice of my feasts” for “the sacrifice of the feast of the Passover.”

10Unless, with Bacon, we are to regard xxiv. 12-14, 18b as original. More probably a later editor has worked up old material of E (of which there are unmistakable traces) in order to include the whole of xx.-xxiii. in the covenant: xxiv. 15-18a are an addition from P.

11The present text of xxiv. 12 also has probably been transposed in accordance with the view that the “judgment” formed part of the covenant, cf. Deut. v. 31. Originally the latter part of the verse must have run, “That I may give thee the tables of stone which I have written, and may teach thee the law and the commandment.” For further details see Bacon,Triple Tradition of Exodus, pp. 111 f., 132 f.

12According to Deut. x. 1 f., which is in the main averbalexcerpt from Ex. xxxiv. 1 f., Yahweh ordered Moses to make an ark of acacia woodbeforehe ascended the mountain.

13To the same hand are to be ascribed also xxvii. 6, 20, 21; xxviii. 41; xxix. 21, 38-41.

EXODUS, THE,the name given to the journey (Gr.ἔξοδος) of the Israelites from Egypt into Palestine, under the leadership of Moses and Aaron, as described in the books of the Bible from Exodus to Joshua. These books contain the great national epic of Judaism relating the deliverance of the people from bondage in Egypt, the overthrow of the pursuing Pharaoh and his army, the divinely guided wanderings through the wilderness and the final entry into the promised land. Careful criticism of the narratives1has resulted in the separation of later accretions from the earliest records, and the tracing of the elaboration of older traditions under the influence of developing religious and social institutions. In the story of the Exodus there have been incorporated codes of laws and institutions which were to be observed by the descendants of the Israelites in their futurehome, and these, really of later origin, have thus been thrown back to the earlier period in order to give them the stamp of authority. So, although a certain amount of the narrativecoulddate from the days of Moses, the Exodus story has been made the vehicle for the aims and ideals of subsequent ages, and has been adapted from time to time to the requirements of later stages of thought. The work of criticism has brought to light important examples of fluctuating tradition, singular lacunae in some places and unusual wealth of tradition in others, and has demonstrated that much of that which had long been felt to be impossible and incredible was due to writers of the post-exilic age many centuries after the presumed date of the events.

The book of Genesis closes with the migration of Jacob’s family into Egypt to escape the famine in Canaan. Jacob died and was buried in Canaan by his sons, who, however, returned again to the pastures which the Egyptian king had granted them in Goshen. Their brother Joseph on his death-bed promised that God would bring them to the land promised to their forefathers and solemnly adjured them to carry up his bones (Gen. 1.). In the book of Exodus the family has become a people.2The Pharaoh is hostile, and Yahweh, the Israelite deity, is moved to send a deliverer; on the events that followed seeExodus, Book of;Moses. It has been thought that dynastic changes occasioned the change in Egyptian policy (e.g.the expulsion of the Hyksos), but if the Israelites built Rameses and Pithom (Ex. i. 11), cities which, as excavation has shown, belong to the time of Rameses II. (13th centuryB.C.), earlier dates are inadmissible. On these grounds the Exodus may have taken place under one of his successors, and since Mineptah or Merneptah (son of Rameses), in relating his successes in Palestine, boasts thatYsiraalis desolated, it would seem that the Israelites had already returned. On the other hand, it has been suggested that when Jacob and his family entered Egypt, some Israelite tribes had remained behind and that it is to these that Mineptah’s inscription refers. The problem is complicated by the fact that, from the Egyptian evidence, not only was there at this time no remarkable emigration of oppressed Hebrews, but Bedouin tribes were then receiving permission to enter Egypt and to feed their flocks upon Egyptian soil. It might be assumed that the Israelites (or at least those who had not remained behind in Palestine) effected their departure at a somewhat later date, and in the time of Mineptah’s successor, Seti II., there is an Egyptian report of the pursuit of some fugitive slaves over the eastern frontier. The value of all such evidence will naturally depend largely upon the estimate formed of the biblical narratives, but it is necessary to observe that these have not yet found Egyptian testimony to support them. Although the information which has been brought to bear upon Egyptian life and customs substantiates the general accuracy of the local colouring in some of the biblical narratives, the latter contain several inherent improbabilities, and whatever future research may yield, no definite trace of Egyptian influence has so far been found in Israelite institutions.

No allusions to Israelites in Egypt have yet been found on the monuments; against the view that the Aperiu (or Apury) of the inscriptions were Hebrews, see S.R. Driver in D.G. Hogarth,Authority and Archaeology, pp. 56 sqq.; H.W. Hogg,Ency. Bib.col. 1310. The plagues of Egypt have been shown to be those to which the land is naturally subject (R. Thomson,Plagues of Egypt), but the description of the relations of Moses and Aaron to the court raises many difficult questions (H.P. Smith,O.T. Hist.pp. 57-60). Those who reject Ex. i. 11 and hold that 480 years elapsed between the Exodus and the foundation of the temple (I Kings vi. 1, seeBible: Chronology) place the former about the time of Tethmosis (Thothmes) III., and suppose that the hostile Ḥabiri (Khabiri) who troubled Palestine in the 15th century are no other than Hebrews (the equation is philologically sound),i.e.the invading Israelites.3But although the evidence of the Amarna tablets might thus support the biblical tradition in its barest outlines, the view in question, if correct, would necessitate the rejection of a great mass of the biblical narratives as a whole.

In the absence of external evidence the study of the Exodus of the Israelites must be based upon the Israelite records, and divergent or contradictory views must be carefully noticed. Regarded simply as a journey from Egypt into Palestine it is the most probable of occurrences: the difficulty arises from the actual narratives. The first stage is the escape from the land of Goshen (q.v.), the district allotted to the family of Jacob (Gen. xlvi. 28-34, xlvii. 1, 4, 6).4As to the route taken across the Red Sea (Yam Sūph) scholars are not agreed (see W.M. Müller,Ency. Bib.col. 1436 sqq.); it depends upon the view held regarding the second stage of the journey, the road to the mountain of Sinai or Horeb and thence to Kadesh. The last-mentioned place is identified with Ain Kadīs, about 50 m. south of Beersheba; but the identification of the mountain is uncertain, and it is possible that tradition confused two distinct places. According to one favourite view, the journey was taken across the Sinaitic peninsula to Midian, the home of Jethro. Others plead strongly for the traditional site Jebel Mūsā or Serbāl in the south of the peninsula (see J.R. Harris,Dict. Bible, iv. pp. 536 sqq.; H. Winckler,Ency. Bib.col. 4641). The latter view implies that the oppressed Israelites left Egypt for one of its dependencies, and both theories find only conjectural identifications in the various stations recorded in Num. xxxiii. But this list of forty names, corresponding to the years of wandering, is from a post-exilic source, and may be based merely upon a knowledge of caravan-routes; even if it be of older origin, it is of secondary value since it represents a tradition differing notably from that in the earlier narratives themselves, and these on inspection confirm Judg. xi. 16 seq., where the Israelites proceed immediately to Kadesh.

Ex. xvi.-xviii. presuppose a settled encampment and a law-giving, and thus belong to a stageafterSinai had been reached (Ex. xix. sqq.). They are closely related, as regards subject matter, &c. , to the narratives in Num. x. 29-xi., xx. 1-13 (Sinai to Kadesh), and the initial step is the recognition that the latter is their original context (see G.F. Moore,Ency. Bib.col. 1443 [v.]). Further, internal peculiarities associating events now at Sinai-Horeb with those at Kadesh support the view that Kadesh was their true scene, and it is to be noticed that in Ex. xv. 22 seq. the Israelites already reach the wilderness of Shur and accomplish the three days’ journey which had been their original aim (cf. Ex. iii. 18, v. 3, viii. 27). The wilderness of Shur (Gen. xvi. 7, xx. 1; 1 Sam. xv. 7, xxvii. 8) is the natural scene of conflicts with Amalekites (Ex. xvii. 8 sqq.), and its sanctuary of Kadesh or En Mishpat (“well of judgment,” Gen. xiv. 7) was doubtless associated with traditions of the giving of statutes and ordinances. The détour to Sinai-Horeb appears to belong to a later stage of the tradition, and is connected with the introduction of laws and institutions of relatively later form. It is foreshadowed by the injunction to avoid the direct way into Palestine (see Ex. xiii. 17-19), since on reaching Kadesh the Israelites would be within reach of hostile tribes, and the conflicts which it was proposed to avoid actually ensued.5The forty years of wandering in the wilderness is characteristic of the Deuteronomic and post-exilic narratives; in the earlier sources the fruitful oasis of Kadesh is the centre, and even after the tradition of a détour to Sinai-Horeb was developed, only a brief period is spent at the holy mountain.

From Kadesh spies were sent into Palestine, and when the people were dismayed at their tidings and incurred the wrath of Yahweh, the penalty of the forty years’ delay was pronounced(Num. xiii. seq.). Originally Caleb alone was exempt and for his faith received a blessing; later tradition adds Joshua and in Deut. i. 37 seq. alludes to some unknown offence of Moses. According to Num. xxi. 1-3 the Israelites (a generalizing amplification) captured Hormah, on the way to Beersheba, and subsequently the clan Caleb and the Kenites (the clan of Moses’ father-in-law) are found in Judah (Judg. i. 16). Although the traditions regard their efforts as part of a common movement (from Gilgal, see below), it is more probable that these (notably Caleb) escaped the punishment which befell the rest of the Israelites, and made their way direct from Kadesh into the south of Palestine.6On the other hand, according to the prevailing tradition, the attempt to break northwards was frustrated by a defeat at Hormah (Num. xiv. 40-45), an endeavour to pass Edom failed, and the people turned back to theYam Sūph(here at the head of the Gulf of Akabah) and proceeded up to the east of Edom and Moab. Conflicting views are represented (on which seeMoab), but at length Shittim was reached and preparations were made to cross the Jordan into the promised land. This having been effected, Gilgal became the base for a series of operations in which the united tribes took part. But again the representations disagree, and to the overwhelming campaigns depicted in the book of Joshua most critics prefer the account of the more gradual process as related in the opening chapter of the book of Judges (seeJews:History, § 8).

Thus, whatever evidence may be supplied by archaeological research, the problem of the Exodus must always be studied in the light of the biblical narratives. That the religious life of Israel as portrayed therein dates from this remote period cannot be maintained against the results of excavation or against the later history, nor can we picture a united people in the desert when subsequent vicissitudes represent the union as the work of many years, and show that it lasted for a short time only under David and Solomon. During the centuries in which the narratives were taking shape many profound changes occurred to affect the traditions. Developments associated with the Deuteronomic reform and the reorganization of Judaism in post-exilic days can be unmistakably recognized, and it would be unsafe to assume that other vicissitudes have not also left their mark. Allowance must be made for the shifting of boundaries or of spheres of influence (Egypt, Edom, Moab), for the incorporation of tribes and of their own tribal traditions, and in particular for other movements (e.g.from Arabia).7If certain clans moved direct from Kadesh into Judah, it is improbable that others made the lengthy détour from Kadesh by the Gulf of Akabah, but this may well be an attempt to fuse the traditions of two distinct migrations. Among the Joseph-tribes (Ephraim and Manasseh), the most important of Israelite divisions, the traditions of an ancestor who had lived and died in Egypt would be a cherished possession, but although most writers agree that not all the tribes were in Egypt, it is impossible to determine their number with any certainty. At certain periods, intercourse with Egypt was especially intimate, and there is much in favour of the view that the name Mizraim (Egypt) extended beyond the borders of Egypt proper. Reference has already been made to other cases of geographical vagueness, and one must recognize that in a body of traditions such as this there was room for the inclusion of the most diverse elements which it is almost hopeless to separate, in view of the scantiness of relevant evidence from other sources, and the literary intricacy of the extant narratives. That many different beliefs have influenced the tradition is apparent from what has been said above, and is especially noticeable from a study of the general features. Thus, although the Israelites possessed cattle (Ex. xvii. 3, xix. 13, xxiv. 5, xxxii. 6, xxxiv. 3; Num. xx. 19), allusion is made to their lack of meat in order to magnify the wonders of the journey, and among divinely sent aids to guide and direct the people upon the march not only does Moses require the assistance of ahumanhelper (Jethro or Hobab), but the angel, the ark, the pillar of cloud and of fire and the mysterious hornet are also provided.

In addition to the references already given, see J.W. Colenso,Pentateuch and Book of Joshua(on internal difficulties); A. Jeremias,Alte Test. im Lichte d. alt. Orients2(pp. 402 sqq., on later references in Manetho, &c. , with which cf. also R.H. Charles,Jubilees, p. 245 seq.); art. “Exodus” inEncy. Bib.; Ed. Meyer,Israëliten(passim); Bönhoff,Theolog. Stud. u. Krit.(1907), pp. 159-217; the histories of Israel and commentaries on the book of Exodus. Among the numerous special works, mention may be made of G. Ebers,Durch Gosen zum Sinai; E.H. Palmer,Desert of the Exodus; O.A. Toffteen,The Historic Exodus; fuller information is given in L.B. Paton,Hist. of Syria and Palestine, p. 34 (also ch. viii.); and C.F. Kent,Beginnings of Heb. Hist.p. 355 seq.

(S. A. C.)

1See the articles on the books in question.2There is a lacuna between the oldest traditions in Genesis and those in Exodus: the latter beginning simply “and there arose a new king over Egypt which knew not Joseph.” The interval between Jacob’s arrival in Egypt and the Exodus is given varyingly as 400 or 430 years (Gen. xv. 13, Ex. xii. 40 seq., Acts vii. 6); but the Samaritan and Septuagint versions allow only 215 years (Ex. loc. cit.), and a period of only four generations is presupposed in Gen. xv. 16 (cf. the length of the genealogies between the contemporaries of Joseph and those of Moses in Ex. vi. 16-20).3Sec,e.g., J. Orr,Problem of the O.T.pp. 422 sqq.; Ed. Meyer,Die Israëliten, pp. 222 sqq. Some, too, find in the Amarna tablets the historical background for Joseph’s high position at the Egyptian court (see Cheyne,Ency. Bib.art. “Joseph”).4For the varying traditions regarding the number of the people and their residence (whether settled apart, cf.,e.g., Gen. xlvi. 34, Ex. viii. 22, ix. 26, x. 23, or in the midst of the Egyptians) see the recent commentaries.5See further J. Wellhausen,Prolegomena, pp. 342 sqq.; G.F. Moore, Ency. Bib. col. 1443; S.A. Cook,Jew. Quart. Rev.(1906), pp. 741 sqq. (1907), p. 122, and art.Moses. Ex. xiii. 17-19 forbids the compromise which would place Sinai-Horeb in the neighbourhood of Kadesh (A.E. Haynes,Pal. Explor. Fund, Quart. Statem.(1896), pp. 175 sqq.; C.F. Kent [seeLit.below], p. 381).6So B. Stade, Steuernagel, Guthe, G.F. Moore, H.P. Smith, C.F. Kent, &c. SeeCaleb;Jerahmeel;Judah;Kenites;Levites; andJews:History, §§ 5, 20 (end).7An instructive parallel to the last-mentioned is afforded by Dissard’s account of the migration of Arab tribes into Palestine in the 18th centuryA.D.(Revue biblique, July 1905).

1See the articles on the books in question.

2There is a lacuna between the oldest traditions in Genesis and those in Exodus: the latter beginning simply “and there arose a new king over Egypt which knew not Joseph.” The interval between Jacob’s arrival in Egypt and the Exodus is given varyingly as 400 or 430 years (Gen. xv. 13, Ex. xii. 40 seq., Acts vii. 6); but the Samaritan and Septuagint versions allow only 215 years (Ex. loc. cit.), and a period of only four generations is presupposed in Gen. xv. 16 (cf. the length of the genealogies between the contemporaries of Joseph and those of Moses in Ex. vi. 16-20).

3Sec,e.g., J. Orr,Problem of the O.T.pp. 422 sqq.; Ed. Meyer,Die Israëliten, pp. 222 sqq. Some, too, find in the Amarna tablets the historical background for Joseph’s high position at the Egyptian court (see Cheyne,Ency. Bib.art. “Joseph”).

4For the varying traditions regarding the number of the people and their residence (whether settled apart, cf.,e.g., Gen. xlvi. 34, Ex. viii. 22, ix. 26, x. 23, or in the midst of the Egyptians) see the recent commentaries.

5See further J. Wellhausen,Prolegomena, pp. 342 sqq.; G.F. Moore, Ency. Bib. col. 1443; S.A. Cook,Jew. Quart. Rev.(1906), pp. 741 sqq. (1907), p. 122, and art.Moses. Ex. xiii. 17-19 forbids the compromise which would place Sinai-Horeb in the neighbourhood of Kadesh (A.E. Haynes,Pal. Explor. Fund, Quart. Statem.(1896), pp. 175 sqq.; C.F. Kent [seeLit.below], p. 381).

6So B. Stade, Steuernagel, Guthe, G.F. Moore, H.P. Smith, C.F. Kent, &c. SeeCaleb;Jerahmeel;Judah;Kenites;Levites; andJews:History, §§ 5, 20 (end).

7An instructive parallel to the last-mentioned is afforded by Dissard’s account of the migration of Arab tribes into Palestine in the 18th centuryA.D.(Revue biblique, July 1905).

EXOGAMY(Gr.ἔξω, outside; andγάμος, marriage), the term proposed by J.F. McLennan for the custom compelling marriage “out of the tribe” (or rather “out of the totem”); its converse is endogamy (q.v.). McLennan would find an explanation of exogamy in the prevalence of female infanticide, which, “rendering women scarce, led at once to polyandry within the tribe, and the capturing of women from without.” Infanticide of girls is, and no doubt ever has been, a very common practice among savages, and for obvious reasons. Among tribes in a primitive stage of social organization girl-children must always have been a hindrance and a source of weakness. They had to be fed and yet they could not take part in the hunt for food, and they offered a temptation to neighbouring tribes. Infanticide, however, is not proved to have been so universal as McLennan suggests, and it is more probable that the reason of exogamy is really to be found in that primitive social system which made the “captured” woman the only wife in the modern sense of the term. In the beginnings of human society children were related only to their mother; and the women of a tribe were common property. Thus no man might appropriate any female or attempt to maintain proprietary rights over her. With women of other tribes it would be different, and a warrior who captured a woman would doubtless pass unchallenged in his claim to possess her absolutely. Infanticide, the evil physical effects of “in-and-in” breeding, the natural strength of the impulse to possess on the man’s part, and the greater feeling of security and a tendency to family life and affections on the woman’s, would combine to make exogamy increase and marriages within the tribe decrease. A natural impulse would in a few generations tend to become a law or a custom, the violation of which would be looked on with horror. Physical capture, too, as soon as increasing civilization and tribal intercommunication removed the necessity for violence, became symbolic of the more permanent and individual relations of the sexes. An additional explanation of the prevalence of exogamy may be found in the natural tendency of exogamous tribes to increase in numbers and strength at the expense of those communities which moved towards decadence by in-breeding. Thus tradition would harden into a prejudice, strong as a principle of religion, and exogamy would become the inviolable custom it is found to be among many races. In Australia, Sir G. Grey writes: “One of the most remarkable facts connected with the natives is that they are divided into certain great families, all the members of which bear the same name ... these family names are common over a great portion of the continent and a man cannot marry a woman of his own family name.” In eastern Africa, Sir R. Burton says: “The Somal will not marry one of the same, or even of a consanguineous family,” and the Bakalahari have the same rule. Paul B. du Chaillu found exogamy the rule and blood marriages regarded as an abomination throughout western Equatorial Africa. In India the Khasias, Juangs, Waralis, Otaons, Hos and other tribes are strictly exogamous. The Kalmucks are divided into hordes, and no man may marry a woman of the same horde. Circassians and Samoyedes have similar rules. The Ostiaks regard endogamy (marriage within the clan) as a crime, as do the Yakuts of Siberia. Among the Indians of America severe rules prescribing exogamy prevail. The Tsimsheean Indians of British Columbia are divided intotribes and totems, or “crests which are common to all the tribes,” says one writer. “The crests are the whale, the porpoise, the eagle, the coon, the wolf and the frog.... The relationship existing between persons of the same crest is nearer than that between members of the same tribe.... Members of the same tribe may marry, but those of the same crest are not allowed to under any circumstances; that is, a whale may not marry a whale, but a whale may marry a frog, &c.” The Thlinkeets, the Mayas of Yucatan and the Indians of Guiana are exogamous, observing a custom which is thus seen to exist throughout Africa, in Siberia, China, India, Polynesia and the Americas.

Authorities.—J.F. McLennan,Primitive Marriage(1865), andStudies in Anc. Hist.(1896); Lord Avebury,Origin of Civilization(1902); Westermarck,History of Human Marriage(1894); A. Lang,Social Origins(1903); L.H. Morgan,Ancient Society(1877); J.G. Frazer,Totemism and Exogamy(1910); see alsoTotem.

EXORCISM(Gr.ἐξορκίζειν, to conjure out), the expulsion of evil spirits from persons or places by incantations, magical rites or other means. As a corollary of the animistic theory of diseases and of belief in Possession (q.v.), we find widely spread customs whose object is to get rid of the evil influences. These customs may take the form of a general expulsion of evils, either once a year or at irregular intervals; the evils, which are often regarded as spirits, sometimes as the souls of the dead, may be expelled, according to primitive philosophy, either immediately by spells, purifications or some form of coercion; or they may be put on the back of a scapegoat or other material vehicle. Among the means of compelling the evil spirits are assaults with warlike weapons or sticks, the noise of musical instruments or of the human voice, the use of masks, the invocation of more powerful good spirits, &c. ; both fire and water are used to drive them out, and the use of iron is a common means of holding them at bay.

The term exorcism is applied more especially to the freeing of an individual from a possessing or disease-causing spirit; the means adopted are frequently the same as those mentioned above; in the East Indies the sufferer sometimes dances round a small ship, into which the spirit passes and is then set adrift. The patient may be beaten or means may be employed whose efficiency depends largely on their suggestive nature. Among the Dakota Indians the medicine-man chantshi-le-li-lah!at the bed of the sick man and accompanies his chant with the rattle; he then sucks at the affected part till the possessing spirit is supposed to come out and take its flight, when men fire guns at it from the door of the tent. The Zulus believe that they can get rid of the souls of the dead, which cause diseases, by sacrifices of cattle, or by expostulating with the spirits; so too theshamanor magician in other parts of the world offers the possessing spirit objects or animals.

The professional exorcist was known among the Jews; in Greece the art was practised by women, and it is recorded that the mothers of Epicurus and Aeschines belonged to this class; both were bitterly reproached, the one by the Stoics, the other by Demosthenes, with having taken part in the practices in question. The prominence of exorcism in the early ages of the Christian church appears from its frequent mention in the writings of the fathers, and by the 3rd century there was an order of exorcists (seeExorcist). The ancient rite of exorcism in connexion with baptism is still retained in the Roman ritual, as is also a form of service for the exorcising of possessed persons. The exorcist signs the possessed person with the figure of the cross, desires him to kneel, and sprinkles him with holy water; after which the exorcist asks the devil his name, and abjures him by the holy mysteries of the Christian religion not to afflict the person possessed any more. Then, laying his right hand on the demoniac’s head, he repeats the form of exorcism as follows: “I exorcise thee, unclean spirit, in the name of Jesus Christ; tremble, O Satan, thou enemy of the faith, thou foe of mankind, who hast brought death into the world, who hast deprived men of life, and hast rebelled against justice, thou seducer of mankind, thou root of evil, thou source of avarice, discord and envy.” Houses and other places supposed to be haunted by unclean spirits are likewise to be exorcised with similar rites, and in general exorcism has a place in all the ceremonies for consecrating and blessing persons or things (seeBenediction).

See Tylor,Primitive Culture; Skeat,Malay Magic, p. 427 seq.; Frazer,Golden Bough, vol. iii. 189; Krafft,Ausführliche Historie von Exorcismus; Koldeweg,Der Exorcismus im Herzogthum Braunschweig; Brecher,Das Transcendentale, Magie, etc. im Talmud, pp. 195-203:Zeitschr. für Assyriologie(Dec. 1893, April 1894); Herzog,Realencykl., s.v.“Exorcismus”; Waldmeier,Autobiography, p. 64; L.W. King,Babylonian Magic; Maury,La Magie; R.C. Thompson,Devils and Evil Spirits of Babylonia.

EXORCIST(Lat.exorcista, Gr.ἐξορκίστης), in the Roman Catholic church, the third grade in the minor orders of the clergy, between those of acolyte and reader. The office, which involves the right of ceremonially exorcising devils (see Exorcism), is actually no more than a preliminary stage of the priesthood. The earliest record of the special ordination of exorcists is the 7th canon of the council of Carthage (A.D.256). “When they are ordained,” it runs, “they receive from the hand of the bishop a little book in which the exorcisms are written, receiving power to lay hands on theenergumeni, whether baptized or catechumens.” Whatever its present position, the office of exorcist was, until comparatively recent times, by no means considered a sinecure. “The exorcist a terror to demons” (Paulinus,Epist.24) survived the Reformation among Protestants, with the belief, expressed by Firmilianus in his epistle to St Cyprian, that “through the exorcists, by the voice of man and the power of God, the devil may be whipped, and burnt and tortured.”

EXOTIC(Gr.ἐξωτικός, foreign, fromἔξω, outside), of foreign origin, or belonging to another country. The term is now used in the restricted sense of something not indigenous or native, and is mostly applied to plants introduced from foreign countries, which have not become acclimatized. Figuratively, “exotic” is used to convey the sense of something rare, delicate or extravagant.

EXPATRIATION(from Late Lat.expatriare, to exile, andpatria, native land), a term used in a general sense for the banishment of a person from his own country. In international law expatriation is the renunciation or change of allegiance to one’s native or adopted country. It may take place either by a voluntary act or by operation of law. Some countries, as France and England, disclaim their subjects if they become naturalized in another country, others, again, passively permit expatriation whether a new nationality has been acquired or not; others, as Germany, make expatriation the consequence of continued absence from their territory. (SeeAlien;Allegiance;Naturalization.)

EXPERT(Lat.expertus, fromexperiri, to try), strictly, skilled, or one who has special knowledge; as used in law, an expert is a person, selected by a court, or adduced by a party to a cause, to give his opinion on some point in issue with which he is peculiarly conversant. In Roman law questions of disputed handwriting were referred to experts; and in France, whenever the court considers that a report by experts is necessary, it is ordered by a judgment clearly setting forth the objects of theexpertise(Code Proc. Civ. art. 302). Three experts are then to be appointed, unless the parties agree upon one only (art. 303). The experts are required to take an oath (art. 305), but in practice this requirement is frequently dispensed with. They may be challenged on the same grounds as witnesses (art. 310). The necessary documentary and other evidence is laid before them (art. 317), and they make a single report to the court, even if they express different opinions: in that case the grounds only of the different opinions are to be stated, and not the personal opinion of each of the experts (art. 318). If the court is not satisfied with the report, new experts may be appointed (art. 322); the judges are not bound to adopt the opinion of the experts (art. 323). “This procedure in regard to experts is common to both the civil and commercial courts, but it is much more frequently resorted to in the commercial court than in the civil court, and the investigation is usually conducted by special experts officially attached to each of these courts” (Bodington,French Law of Evidence, London, 1904, p. 102).A similar system is to be found in force in many other European countries; seee.g.Codes of Civil Procedure of Holland, arts. 222 et seq.; Belgium, arts. 302 et seq.; Italy, arts. 252 et seq.; as well as in those colonies where French law has been followed (Codes of Civil Procedure of Quebec, arts. 392 et seq.; St Lucia, arts. 286 et seq.). In Mauritius the articles of the French law, summarized above, are still nominally in force; but in practice each side calls its own expert evidence, as in England.

There is some evidence that in England the courts were in early times in the habit of summoning to their assistance, apparently as assessors, persons specially qualified to advise upon any scientific or technical question that required to be determined. Thus “in an appeal of maihem (i.e.wounding) ... the court did not know how to adjudge because the wound was new, and then the defendant took issue and prayed the court that the maihem might be examined, on which a writ was sent to the sheriff to cause to comemedicos chirurgieos de melioribus London, ad informandum dominum regem el curiam de his quae eis ex parte domini regis injungerentur” (Year Book, 21 Hen. VII. pl. 30, p. 33). The practice of calling in expert assistance in judicial inquiries was not confined to medico-legal cases. “If matters arise,” said Justice Saunders inBuckleyv.Rice Thomas(1554, Plowden, 124 a), “which concern other faculties, we commonly apply for the aid of that science or faculty which it concerns.” English procedure, however, beinglitigious, and not, like continental European procedure,inquisitorial, in its character, the expert soon became, and still is, simply a witness to speak to matters of opinion.

There is a considerable body of law in England as to expert evidence. Only a few points can be touched upon here. (1) An expert is permitted to refresh his memory in regard to any fact by referring to anything written by himself or under his direction at the time when the fact occurred or at a time when it was fresh in his memory. This is also law generally in the United States (seee.g.New York Civil Code, s. 1843). In Scotland, medical and other scientific reports are lodged in process before the trial, and the witness reads them as part of his evidence and is liable to be examined or cross-examined on their contents. (2) In strictness, an expert will not be allowed, in cases of alleged insanity, to say that a litigating or incriminated party is insane or the reverse, and so to usurp the prerogative of the court or jury. But he may be asked whether certain facts or symptoms,assuming them to be proved, are or are not indicative of insanity. But in practice this rule is relaxed both in England and in Scotland, and (where it exists) to a still greater extent in America. (3) Foreign law can only be proved in English courts—and the same rule applies in Scotland—(a) by obtaining an opinion on the subject from a superior court of the country whose laws are in dispute under the Foreign Law Ascertainment Act 1861 or the British Law Ascertainment Act 1859, or (b) by the evidence of a lawyer of the country whose law is in question, or who has studied itin that country, or of an official whose position requires, and therefore presumes, a sufficient knowledge of that law. (4) The weight of authority both in England and in America supports the view that an expert is not bound to give evidence as to matters of opinion unless upon an undertaking by the party calling him to pay a reasonable remuneration for his evidence.

Statutory provision has been made in England for the summoning of expert assistance by the legal tribunals in various cases. In the county courts the judge may, if he thinks fit, on the application of either party, call in as assessor one or more persons of skill and experience as to the matters in dispute (County Courts Act 1888, s. 103), and special provision is made for calling in an assessor in employers’ liability cases (act of 1880, s. 6) and admiralty matters (see County Courts Admiralty Jurisdiction Acts of 1868 and 1869). In the High Court and court of appeal one or more specially qualified assessors may be called in to assist in the hearing of any cause or matter except a criminal proceeding by the crown (Judicature Acts 1873, s. 56), and a like power is given to both these courts and the judicial committee of the privy council in patent cases (Patents, &c. , Act 1883., s. 28). Maritime causes, whether original or on appeal from county courts, are usually taken in the presence of Elder Brethren of the Trinity House, who advise the judge without having any right to control or any responsibility for his decision (see the “Beryl,” 1884, 9 P.D. 1), and on appeal in maritime causes nautical assessories are usually called in by the court of appeal, and may be called in by the House of Lords (Judicature Act 1891, s. 3); a like provision is made as to maritime causes in Scottish courts (Nautical Assessors [Scotland] Act 1894). The judicial committee of the privy council, besides its power to call in assessors in patent cases, is authorized to call them in in ecclesiastical causes (Appellate Jurisdiction Act 1876, s. 14).

In addition to the authorities cited in the text, see Taylor,Law of Evidence(9th ed., London, 1895); J.D. Lawson,Law of Expert and Opinion Evidence(1900).

EXPLOSIVES,a general term for substances which by certain treatment “explode,”i.e.decompose or change in a violent manner so as to generate force. From the manner and degree of violence of the decomposition they are classified into “propellants” and “detonators,” but this classification is not capable of sharp delimitation. In some cases the same substance may be employed for either purpose under altered external conditions; but there are some substances which could not possibly be employed as propellants, and others which can scarcely be induced to explode in the manner known as “detonation.” A propellant may be considered as a substance that on explosion produces such a disturbance that neighbouring substances are thrown to some distance; a detonator or disruptor may produce an extremely violent disturbance within a limited area without projecting substances to any great distance. Time is an important, perhaps the most important, factor in this action. A propellant generally acts byburningin a more or less rapid and regular manner, producing from a comparatively small volume a large volume of gases; during this action heat is also developed, which, being expended mostly on the gaseous products, causes a further expansion. The noise accompanying an explosion is due to an air wave, and is markedly different in the case of a detonator from a real propellant. Some cases of ordinary combustion can be accelerated into explosions by increasing the area of contact between the combustible and the oxygen supplier, for instance, ordinary gas or dust explosions. Neither temperature nor quantity of heat energy necessarily gives an explosive action. Some metals,e.g.aluminium and magnesium, will, in oxidizing, produce a great thermal effect, but unless there be some gaseous products no real explosive action.

Explosives may be mechanical mixtures of substances capable of chemical interaction with the production of large volumes of gases, or definite chemical compounds of a peculiar class known as “endothermic,” the decomposition of which is also attended with the evolution of gases in large quantity.

All chemical compounds are either “endothermic” or “exothermic.” In endothermic compounds energy, in some form, has been taken up in the act of formation of the compound. Some of this energy has become potential, or rather the compound formed has been raised to a higher potential. This case occurs when two elements can be united only under some compulsion such as a very high temperature, by the aid of an electric current, or spark, or as a secondary product whilst some other reactions are proceeding. For example, oxygen and nitrogen combine only under the influence of an electric spark, and carbon and calcium in the electric furnace. The formation of chlorates by the action of chlorine on boiling potash is a good instance of a complex compound (potassium chlorate), being formed in small quantity as a secondary product whilst a large quantity of primary and simpler products (potassium chloride and water) is forming. In chlorate formation the greater part of the reaction represents a running down of energy and formation of exothermic compounds, with only a small yield of an endothermic substance. Another idea of the meaning of endothermic is obtained from acetylene. When 26 parts by weight of this substance are burnt, the heat produced will warm up 310,450 parts of water 1° C. Acetylene consists of 24 parts of carbon and 2 of hydrogen by weight. The 24 parts of carbon will, if in the form of pure charcoal, heat 192,000 parts of water 1°, and the 2 parts of hydrogen will heat 68,000 parts of water 1°, the total heat production being 260,000 heat units. Thus 26 grams of acetylene give an excess of 50,450 units over the amount given by the constituents. This excess ofheat energy1is due to some form of potential energy in the compound which becomes actual heat energy at the moment of dissolution of the chemical union. The manner in which a substance is endothermic is of importance as regards the practical employment of explosives. Some particular endothermic state or form results from the mode of formation and the consequent internal structure of the molecule. Physical structure alone can be the cause of a relative endothermic state, as in the glass bulbs known as Rupert’s drops, &c. , or even in chilled steel. Rupert’s drops fly in pieces on being scratched or cut to a certain depth. The cause is undoubtedly to be ascribed to the molecular state of the glass brought about by chilling from the melted state. The molecules have not had time to separate or arrange themselves in easy positions. In steel when melted the carbide of iron is no doubt diffused equally throughout the liquid. When cooled slowly some carbide separates out more or less, and the steel is soft or annealed. When chilled the carbides are retained in solid solution. The volume of chilled glass or steel differs slightly from that in the annealed state.Superfused substances are probably in a similar state of physical potential or strain. Many metallic salts, and organic compounds especially, will exhibit this state when completely melted and then allowed to cool in a clean atmosphere. On touching with a little of the same substance in a solid state the liquids will begin to crystallize, at the same time becoming heated almost up to their melting-points. The metal gallium shows this excellently well, keeping liquid for years until touched with the solid metal, when there is a considerable rise of temperature as solidification takes place.All carbon compounds, excepting carbon dioxide, and many if not all compounds of nitrogen, are endothermic. Most of the explosives in common use contain nitrogen in some form.Exothermic compounds are in a certain sense the reverse of endothermic; they are relatively inert and react but slowly or not at all, unless energy be expended upon them from outside. Water, carbon dioxide and most of the common minerals belong to this class.

Superfused substances are probably in a similar state of physical potential or strain. Many metallic salts, and organic compounds especially, will exhibit this state when completely melted and then allowed to cool in a clean atmosphere. On touching with a little of the same substance in a solid state the liquids will begin to crystallize, at the same time becoming heated almost up to their melting-points. The metal gallium shows this excellently well, keeping liquid for years until touched with the solid metal, when there is a considerable rise of temperature as solidification takes place.

All carbon compounds, excepting carbon dioxide, and many if not all compounds of nitrogen, are endothermic. Most of the explosives in common use contain nitrogen in some form.

Exothermic compounds are in a certain sense the reverse of endothermic; they are relatively inert and react but slowly or not at all, unless energy be expended upon them from outside. Water, carbon dioxide and most of the common minerals belong to this class.

The explosives actually employed at the present time include mixtures, such as gunpowders and some chlorate compositions, the ingredients of which separately may be non-explosive; compounds used singly, as guncotton, nitroglycerin (in the form of dynamite), picric acid (as lyddite or melinite), trinitrotoluene, nitrocresols, mercury fulminate, &c. ; combinations of some explosive compounds, such as cordite and the smokeless propellants in general use for military purposes; and, finally, blasting and detonating or igniting compositions, some of which contain inert diluting materials as well as one or more high explosives. Many igniting compositions are examples of the last type, consisting of a high explosive diluted with a neutral substance, and frequently containing in addition a composition which is inflamed by the explosion of the diluted high explosive, the flame in turn igniting the actual propellant.

Explosive Mixtures.—The explosive mixture longest known is undoubtedly gunpowder (q.v.) in some form—that is, a mixture of charcoal with sulphur and nitre, the last being the oxygen provider. Besides the nitrates of metals and ammonium nitrate, there is a limited number of other substances capable of serving in a sufficiently energetic manner as oxygen providers. A few chlorates, perchlorates, permanganates and chromates almost complete the list. Of these the sodium, potassium and barium chlorates are best known and have been actually tried, in admixture with some combustible substances, as practical explosives. Most other metallic chlorates are barred from practical employment owing to instability, deliquescence or other property.

Of the chlorates those of potassium and sodium are the most stable, and mixtures of either of these salts with sulphur or sulphides, phosphorus, charcoal, sugar, starch, finely-ground cellulose, coal or almost any kind of organic,i.e.carbon, compound, in certain proportions, yield an explosive mixture. In many cases these mixtures are not only fired or exploded by heating to a certain temperature, but also by quite moderate friction or percussion. Consequently there is much danger in manufacture and storage, and however these mixtures have been made up, they are quite out of the question as propellants on account of their great tendency to explode in the manner of a detonator. In addition they are not smokeless, and leave a considerable residue which in a gun would produce serious fouling.

Mixtures of chlorates with aromatic compounds such as the nitro- or dinitro-benzenes or even naphthalene make very powerful blasting agents. The violent action of a chlorate mixture is due first to the rapid evolution of oxygen, and also to the fact that a chlorate can be detonated when alone. A drop of sulphuric acid will start the combustion of a chlorate mixture. In admixture with sulphur, sulphides and especially phosphorus, chlorates give extremely sensitive compositions, some of which form the basis of friction tube and firing mixtures.

Potassium and sodium perchlorates and permanganates make similar but slightly less sensitive explosive mixtures with the above-mentioned substances. Finely divided metals such as aluminium or magnesium give also with permanganates, chlorates or perchlorates sensitive and powerful explosives. Bichromates, although containing much available oxygen, form but feeble explosive mixtures, but some compounds of chromic acid with diazo compounds and some acetylides are extremely powerful as well as sensitive. Ammonium bichromate is a self-combustible after the type of ammonium nitrate, but scarcely an explosive.

Explosive Compounds.—Nearly all the explosive compounds in actual use either for blasting purposes or as propellants are nitrogen compounds, and are obtained more or less directly from nitric acid. Most of the propellants at present employed consist essentially of nitrates of some organic compound, and may be viewed theoretically as nitric acid, the hydrogen of which has been replaced by a carbon complex; such compounds are expressed by M·O·NO2, which indicates that the carbon group is in some manner united by means of oxygen to the nitrogen group. Guncotton and nitroglycerin are of this class. Another large class of explosives is formed by a more direct attachment of nitrogen to the carbon complex, as represented by M·NO2. A number of explosives of the detonating type are of this class. They contain the same proportions of oxygen and nitrogen as nitrites, but are not nitrites. They have been termed nitro-derivatives for distinction. One of the simplest and longest-known members of this group is nitrobenzene, C6H5NO2, which is employed to some extent as an explosive, being one ingredient in rack-a-rock and other blasting compositions. The dinitro-benzenes, C6H4(NO2)2, made from it are solids which are somewhat extensively employed as constituents of some sporting powders, and in admixture with ammonium nitrate form a blasting powder of a “flameless” variety which is comparatively safe in dusty or “gassy” coal seams.

Picric acid or trinitrophenol, C6H2·OH·(NO2)3is employed as a high explosive for shell, &c. It requires, however, either to be enclosed and heated, or to be started by a powerful detonator to develop its full effect. Its compounds with metals, such as the potassium salt, C6H2·OK·(NO2)3, are when dry very easily detonated by friction or percussion andalwayson heating, whereas picric acid itself will burn very quietly when set fire to under ordinary conditions. Trinitrotoluene, C6H2·CH3·(NO2)3, is a high explosive resembling picric acid in the manner of its explosion (to which in fact it is a rival), but differs therefrom in not forming salts with metals. The nitronaphthols, C10H6·OH·NO2, and higher nitration products may be counted in the list. Their salts with metals behave much like the picrates.

All these nitro compounds can be reduced by the action of nascent hydrogen to substances called amines (q.v.), which are not always explosive in themselves, but in some cases can form nitrates of a self-combustible nature. Aminoacetic acid, for instance, will form a nitrate which burns rapidly but quietly, and might be employed as an explosive. By the action of nitrous acid at low temperatures on aromatic amines,e.g.aniline, C6H5NH2, diazo compounds are produced. These are all highly explosive, and when in a dry state are for the most part also extremely sensitive to friction, percussion or heat. As many of these diazo compounds contain no oxygen their explosive nature must be ascribed to the peculiar state of union of the nitrogen. This state is attempted to be shown by the formulae such as, forinstance, C6H5·N:N·X, which maybe some compound of diazobenzene. Probably the most vigorous high explosive at present known is the substance called hydrazoic acid or azoimide (q.v.). It forms salts with metals such as AgN3, which explode in a peculiar manner. The ammonium compound, NH4N3, may become a practical explosive of great value.

Mercuric fulminate, HgC2N2O2, is one of the most useful high explosives known. It is formed by the action of a solution of mercurous nitrate, containing some nitrous acid, on alcohol. It is a white crystalline substance almost insoluble in cold water and requiring 130 times its weight of boiling water for solution. It may be heated to 180° C. before exploding, and the explosion so brought about is much milder than that produced by percussion. It forms the principal ingredient in cap compositions, in many fuses and in detonators. In many of these compositions the fulminate is diluted by mixture with certain quantities of inert powders so that its sensitiveness to friction or percussion is just so much lowered, or slowed down, that it will fire another mixture capable of burning with a hot flame. For detonating dynamite, guncotton, &c. , it is generally employed without admixture of a diluent.

Smokeless Propellants.—Gunpowders and all other explosive mixtures or compounds containing metallic salts must form smoke on combustion. The solids produced by the resolution of the compounds are in an extremely finely-divided state, and on being ejected into the atmosphere become more or less attached to water vapour, which is so precipitated, and consequently adds to the smoke. The simplest examples of propellants of the smokeless class are compressed gases. Compressed air was the propellant for the Zalinski dynamite gun. Liquefied carbon dioxide has also been proposed and used to a slight extent with the same idea. It is scarcely practical, however, because when a quantity of a gas liquefied by pressure passes back again into the gaseous state, there is a great absorption of heat, and any remaining liquid, and the containing vessel, are considerably cooled. Steam guns were tried in the American Civil War in 1864; but a steam gun is not smokeless, for the steam escaping from the long tube or gun immediately condenses on expansion, forming white mist or smoke.

At the earliest stage of the development of guncotton the advantage of its smokeless combustion was fully appreciated (seeGuncotton). That it did not at once take its position asthesmokeless propellant, was simply due to its physical state—a fibrous porous mass—which burnt too quickly or even detonated under the pressure required in fire-arms of any kind. In the early eighties of the 19th century it was found that several substances would partly dissolve or at least gelatinize guncotton, and the moment when guncotton proper was obtained as a colloid or jelly was the real start in the matter of smokeless propellants.

Guncotton is converted into a gelatinous form by several substances, such as esters,e.g.ethyl acetate or benzoate, acetone and other ketones, and many benzene compounds, most of which are volatile liquids. On contact with the guncotton a jelly is formed which stiffens as the evaporation of the gelatinizing agent proceeds, and finally hardens when the evaporation is complete. Whilst in a stiff pasty state it may be cut, moulded or pressed into any desired shape without any danger of ignition. In fact guncotton in the colloid state may be hammered on an anvil, and, as a rule, only the portion struck will detonate or fire. Guncotton alone makes a very hard and somewhat brittle mass after treatment with the gelatinizing agent and complete drying, and small quantities of camphor, vaseline, castor oil and other substances are incorporated with the gelatinous guncotton to moderate this hard and brittle state.

All the smokeless powders, of which gelatinized guncottons or nitrated celluloses are the base, are moulded into some conveniently shaped grain,e.g.tubes, cords, rods, disks or tablets, so that the rate of burning may be controlled as desired. The Vieille powder, invented in 1887 and adopted in France for a magazine rifle, consisted of gelatinized guncotton with a little picric acid. Later a mixture of two varieties of guncotton gelatinized together was used. In addition to guncottons other explosive or non-explosive substances are contained in some of these powders. Guncotton alone in the colloid state burns very slowly if in moderate-sized pieces, and when subdivided or made into thin rods or strips it is still very mild as an explosive, partly from a chemical reason, viz. there is not sufficient oxygen in it to burn the carbon to dioxide. Many mixtures are consequently in use, and many more have been proposed, which contain some metallic salt capable of supplying oxygen, such as barium or ammonium nitrate, &c. , the idea being to accelerate the rate of burning of the guncotton and if possible avoid the production of smoke.

The discovery by A. Nobel that nitroglycerin could be incorporated with collodion cotton to form blasting gelatin (seeDynamite) led more or less directly to the invention of ballistite, which differs from blasting gelatin only in the relative amounts of collodion, or soluble nitrated cotton, and nitroglycerin. Ballistite was adopted by the Italian government in 1890 as a military powder. Very many substances and mixtures have been proposed for smokeless powder, but the two substances, guncotton and nitroglycerin, have for the most part kept the field against all other combinations, and for several reasons. Nitroglycerin contains a slight excess of oxygen over that necessary to convert the whole of the carbon into carbon dioxide; it burns in a more energetic manner than guncotton; the two can be incorporated together in any proportion whilst the guncotton is in the gelatinous state; also all the liquids which gelatinize guncotton dissolve nitroglycerin, and, as these gelatinizing liquids evaporate, the nitroglycerin is left entangled in the guncotton jelly, and then shares more or less its colloidal character. In burning the nitroglycerin is protected from detonation by the gelatinous state of the guncotton, but still adds to the rate of burning and produces a higher temperature.

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