Lighting Appliances
The commercial supply of current is covered by a series of articles of which the first to be read isElectricity Supply(Vol. 9, p. 193), to which Emile Garcke, the famous electrical engineer, contributes a section.Power Transmission,Electrical(Vol. 22, p. 233), is by Louis Bell, chief engineer of the General Electric Co., Boston; and contains full details as to the use of both two-phase and three-phase generators in transmission.Induction Coil(Vol. 14, p. 502) andTransformers(Vol. 27, p. 173) are both fully illustrated.Lighting,Electric(Vol. 16, p. 659) deals with arc, incandescent and vapour lamps, and with wiring. The section on household work gives excellent practical information about the best arrangements of lights. A special class of electric light supplies is discussed inLighthouse(Vol. 16, p. 627), by W. T. Douglass, who erected the new Eddystone and the Bishop’s Rock lights, and by N. G. Gedye, another practical expert.
The appliances used to convert current back again into the mechanical energy from which it had been derived are described in the articleMotors, Electric(Vol. 18, p. 910). This article divides continuous current motors into five classes:Separately excited;series-wound constant current;series-wound constant potential;series-wound interdependent current and potential; andshunt-wound constant potential. Alternating current motors are similarly classified asSynchronous constant potential;induction-polyphase constant potential;induction monophase constant potential;repulsion commutating, andseries-commutating.
Trolley Cars and Railroads
Machinery for applying electric power to transportation, both for trolley cars and heavy railroad traffic, is described in the articleTraction(Vol. 27, p. 118), by Prof. Louis Duncan, who designed the first electric locomotives employed with large loads—those introduced in 1895 by the Baltimore & Ohio R.R. for its track in the tunnel under Baltimore. The article gives, with many mechanical diagrams, accounts of the appliances by which the current is taken from trolley wires, conduits and third rails, and of the types of motors and controllers employed.Crane(Vol. 7, p. 368), by Walter Pitt, describes the peculiar type of “crane-rated” motor, by the aid of which steam and hydraulic cranes can be displaced. The electric furnaces used for the reduction of ores and for manufacturing processes in which exceptionally high temperatures are required,are treated inElectrometallurgy(Vol. 9, p. 232), by W. G. M’Millan, lecturer on metallurgy at Mason College, Birmingham. Electric machinery for the refining of metals is dealt with in the articleElectrochemistry(Vol. 9, p. 208). UnderSurgical Instruments(Vol. 26, p. 133) there is a description of the apparatus used for cautery and for illuminating parts of the interior of the body. The appliances used inElectrotherapeuticsare dealt with under that heading (Vol. 9, p. 249). Information as to other medical and surgical apparatus will be found underRöntgen Rays(Vol. 23, p. 694),X-Ray Treatment(Vol. 28, p. 887), by Dr. H. L. Jones, of St. Bartholomew’s Hospital, London; andFluorescence(Vol. 10, p. 575), by Prof. J. R. Cotter, of Trinity College, Dublin.
Telegraph and Telephone
Telegraph(Vol. 26, p. 510), equivalent in length to 70 pages of this Guide, and fully illustrated, is by a number of contributors, and discusses both land lines and submarine cables. The section on instruments, by H. R. Kempe, electrician to the General Post Office, London, includes a full description of the transmitters and receivers employed in the various systems of wireless telegraphy.Telephone(Vol. 26, p. 547) deals with the fixed and portable instruments, the batteries and switchboards, the new automatic exchange “selectors,” and with special applications of the microphone.
A number of other electric appliances are discussed in separate articles, such asBell(Vol. 3, p. 692), by H. M. Ross, in which burglar alarm devices are described; andVentilation,Fan(Vol. 27, p. 1011), by James Bartlett; while sparking plugs and other ignition appliances are treated underOil Engine(Vol. 20, p. 35).
There are also a number of appliances used mostly in experimental and educational work. Such, for instance, areElectrical or Electrostatic Machine(Vol. 9, p. 176), with many illustrations;Electrophorus(Vol. 9, p. 237), andLeyden Jar(Vol. 16, p. 528).
The metals, chemicals and other materials sold by dealers in electrical supplies, and their properties and uses, are described inCopper(Vol. 7, p. 102),Zinc(Vol. 28, p. 981),Lead(Vol. 16, p. 314),Sulphuric Acid(Vol. 26, p. 65),Sodium,Compounds(Vol. 25, p. 341);Chromium(Vol. 6, p. 296);Nitrogen,Compounds(Vol. 19, p. 715);Sal Ammoniac(Vol. 24, p. 59),Bichromates and Chromates(Vol. 3, p. 912),Carbon(Vol. 5, p. 305),Rubber(Vol. 23, p. 795), andGutta Percha(Vol. 12, p. 743).
The following is a partial list, in alphabetical order, of articles of peculiar interest to dealers in electrical supplies.
CHAPTER XIIFOR MERCHANTS AND MANUFACTURERS OF CHEMICALS AND DRUGS
A Factor in All Industries
The chemical and drug industry is not only in itself an enormous business, but it supplies essential materials for almost every branch of manufacturing. Chemical products are employed in our buildings, our clothing, our food; we come into the world and go out of the world with the odour of chemicals about us. The manufacturer or dealer cannot analyze all the influences that affect his market, and when he tries, as he must, to consider the future of the trade, to reckon with the channels of demand that will arise in the course of new applications of chemical products, he is facing all the problems of all the industries.
The variety of raw materials from which chemical products are derived, and the activity with which new sources are discovered and developed, are almost as bewildering. Only a century has passed since coal-tar was first distilled, and to-day no chemist would venture to fix the limits of its industrial possibilities. Electrolysis has been in use since 1804, and yet the future of the world’s wheat supply probably depends upon processes, as yet hardly beyond the experimental stage, of utilizing atmospheric nitrogen.
In connection with so comprehensive an industry, the uses of the Britannica are so manifold that this whole Guide might be devoted to them. Articles on every manufacturing process touch upon the use of chemicals. The articles on countries, states and cities are full of relevant information; and there is hardly a scientific article that would not be helpful. But the 40 general articles on chemistry, the 350 on chemical compounds, and the 75 on manufactured products call most immediately for attention; and, with the aid of other chapters in the Guide, the reader who desires to go further will easily find his way.
Articles on Chemicals
The articleChemistry(Vol. 6, p. 33), equivalent to 135 pages of this Guide, is divided into 6 sections. The first,History, traces the general trend of the science from its infancy to the foundations of the modern theory. The second section,Principles, treats of nomenclature, formulæ, chemical equations and chemical changes. It provides a brief but complete introduction to the terminology and methods of the chemist, and there is not a line in it which will not prove of value in some way or other to the chemical manufacturer. Sections 3 and 4 are devoted toInorganic and Organic Chemistry, giving a history of the subjects and the principles underlying the structure of compounds, with cross references to all articles dealing with their preparation and properties. Sections 5 and 6 deal, respectively, withAnalyticalandPhysical Chemistry.
Dr. Walter Nernst, professor of physical chemistry, University of Berlin, is the author ofChemical Action(Vol. 6, p. 26), which deals specifically with the nature of chemical forces and deduces the laws of chemical statics and kinetics. Of interest and importance in connection with the manufacture of chemicals isSolution(Vol. 25, p. 368), by W. C. D. Whetham, of Cambridge University, author ofTheory of Solution, etc. Another theoretical article which will be foundwidely useful isThermochemistry(Vol. 26, p. 804), by Prof. James Walker, of Edinburgh University. For further details see the chapter onChemistryin this Guide.
Manufacture of Chemicals
It is possible here to mention only a small amount of the material dealing with the manufacture of chemicals. At the end of this chapter there is a fuller alphabetical list. It may be noted, however, that the articles on the elements, metallic and non-metallic, give much consideration to their compounds, how these are made and how used in the arts and in medicine. But in addition to this there are many noteworthy contributions dealing with chemical manufacture. For instance,Alkali Manufacture(Vol. 1, p. 674), by Dr. Georg Lunge, professor of technical chemistry, Zurich Polytechnic, 11 pages in length and with 10 illustrations. The chief processes described are the Leblanc, ammonia-soda, and electrolytic, together with others dependent upon them. The facts about the manufacture of the carbonate, hydrate, and sulphate of soda, chlorine, hydrochloric acid, etc., are fully given.Potassium(Vol. 22, p. 197) treats of the commercial compounds of this metal in the same manner.Nitrogen(Vol. 19, p. 714) explains the new process for the commercial manufacture of nitric acid from atmospheric air—a matter of enormous industrial importance—and also the conversion of nitrogen into ammonia, which has been done successfully only within the past few years.
The manufacture of chemical products by the use of electricity is the subject ofElectrochemistry(Vol. 9, p. 208), and a still larger field is covered byElectrometallurgy(Vol. 9, p. 232). Both of these valuable articles are by W. G. M‘Millan, formerly secretary of the Institute of Electrical Engineers of Great Britain.Sulphuric Acid(Vol. 26, p. 65), illustrated, by Dr. Lunge, describes the properties, reactions and manufacture of the most important of all chemicals, including the more modern contact processes.
Drugs, Origin and Manufacture
As a key to the subject of the origin and manufacture of drugs, the articlePharmacology(Vol. 21, p. 347), by Dr. Ralph Stockman, professor of materia medica and therapeutics in the University of Glasgow, presents a great amount of interesting and valuable information on the action of chemical substances (apart from foods) on all kinds of animals, from bacteria up to man. A short history of pharmacology is given and a large part of the article concerns the action of drugs. There is also a classification of drugs according to the latest and most scientific methods into twenty-eight groups, describing the effects of each group. An appendix to the article, by Dr. H. L. Hennessy, is entitledTerminology in Therapeutics, and is a general explanation of the common names used in the therapeutic classification of drugs.
Since therapeutics is concerned with the remedial power of drugs and the conditions under which they are to be used, the articleTherapeutics(Vol. 26, p. 793), by Dr. Sir Lauder Brunton, of St. Bartholomew’s Hospital, London, and author of the well-known treatise,Modern Therapeutics, should not be overlooked, norPoison(Vol. 21, p. 893), by Dr. Sir Thomas Stevenson, lecturer on chemistry and forensic medicine at Guy’s Hospital, London, wherein all poisons are classified and their antidotes are indicated.
Pharmacy(Vol. 21, p. 355), by E. M. Holmes, of the Pharmaceutical Museum, London, is largely historical in its nature, and yields much interesting and valuable information about the pharmacist. We learn that an Egyptian papyrus of the date 2300 B.C. gives direction as to the preparation of prescriptions, and that diachylon plaster, invented by Menecratesin A.D. 1, is used for the same purposes to-day. A great deal of curious knowledge about ancient remedies, such as the thigh bone of a hanged man, moss grown on a human skull, the ashes of the head of a coal-black cat, etc., renders this article especially entertaining.Pharmacopœia(Vol. 21, p. 353), also by Mr. Holmes, tells about the pharmacopœias in use in different countries, the standardization of drugs, etc.
In the list at the end of this chapter are noted the numerous separate articles on drugs, their preparation and use that appear in the Britannica. Mention should be made of the articles on the elements, such asIron(Vol. 14, p. 799),Arsenic(Vol. 2, p. 653),Mercury(Vol. 18, p. 158),Iodine(Vol. 14, p. 725),Bromine(Vol. 4, p. 633),Sodium(Vol. 25, p. 343),Potassium(Vol. 22, p. 200),Magnesium(Vol. 17, p. 321),Bismuth(Vol. 4, p. 11). Separate sections dealing with pharmacology are found in the articles on very many plants, such asAloe(Vol. 1, p. 720),Anise(Vol. 2, p. 55),Arrowroot(Vol. 2, p. 649),Iceland Moss(Vol. 14, p. 241),Cinchona(Vol. 6, p. 369),Coca(Vol. 6, p. 614),Colchicum(Vol. 6, p. 661),Dandelion(Vol. 7, p. 801),Hop(Vol. 13, p. 678),Horehound(Vol. 13, p. 692),Lobelia(Vol. 16, p. 837),Mint(Vol. 18, p. 557),Mustard(Vol. 19, p. 97),Peppermint(Vol. 21, p. 128), etc.
Biographies of Eminent Scientists
The scientific biographies include not a few subjects which will be of interest, owing to familiarity with the names, to those engaged in the chemical and drug business. Among these areLister, Baron Joseph L.(Vol. 16, p. 777), to whose work and teaching the present importance of the manufacture of antiseptics is largely due;Pasteur, Louis(Vol. 20, p. 892);Curie, Pierre, andMme. Marie Curie(Vol. 7, p. 644), the physicists who first announced the existence of radium;Liebig, Baron J. von(Vol. 16, p. 590), the great physiological chemist;Lunge, Georg(Vol. 17, p. 126), the noted expert in technical chemistry, already mentioned as a contributor to the Britannica, andGlauber, J. R.(Vol. 12, p. 114), the German chemist who made a living chiefly by the sale of secret chemical and medicinal preparations.
The manufacturer of or dealer in food products must of necessity be interested in questions of transportation by land and sea, of taxation, of agriculture, stock-raising and fishing, for example. For all such subjects as these he is referred to other chapters of this Guide. Here he will find only the chief articles on the subjects most closely related to the study of food products. But on these he may glean a wealth of information that will be of greatest value to him, and from them he can turn readily and with profit to a survey of the larger area covered by other chapters.
As a general introduction to the subject the student should readDietetics(Vol. 8, p. 214), by the late Dr. W. O. Atwater, who was in charge of the Nutrition Investigation of the U. S. Department of Agriculture, and R. D. Milner, also of that Department. This article deals with the composition and nutritive values of foods, their fuel value, quantities of nutriments needed, hygienic and pecuniary economy of foods (with tables showing the percentage composition of common food materials), conditions of digestibility, and other matters of equal importance.Nutrition(Vol. 19, p. 920), by Prof. D. N. Paton and Dr. E. P. Cathcart, both of the University of Glasgow, discusses more particularly digestion and the utilization of the different food constituents.
Food Preservation
After establishing the value and relative importance of the various substances used as food, it is of great interest to everyone in the business to consider the subject ofFood Preservation(Vol. 10, p. 612), an article by Otto Hehner, formerly president of the Society of PublicAnalysts, in which there are separate sections onPreservation by Heat(which includes all canning processes);by Chemicals;by Drying;by Refrigeration;by Pickling. The sterilization of milk, condensed milk and milk powder all fall within the scope of this article. The preservation of food by cold is described in fuller detail in the articleRefrigerating and Ice Making(Vol. 23, p. 30), by T. B. Lightfoot, author of the standard technical book on that subject. Among the separate articles on preservative materials areVinegar(Vol. 28, p. 96),Acetic Acid(Vol. 1, p. 135),Citric Acid(Vol. 6, p. 397),Oils(Vol. 20, p. 43),Salt(Vol. 24, p. 87),Saltpetre(Vol. 24, p. 93),Sugar(Vol. 26, p. 32),Borax(Vol. 4, p. 243),Formalin or Formaldehyde(Vol. 10, p. 667),Benzoic Acid(Vol. 3, p. 756),Salicylic Acid(Vol. 24, p. 69),Sulphur,Compounds(Vol. 26, p. 63),Alcohol(Vol. 1, p. 525).
Adulteration
The objections to the use of some of these chemicals are discussed inAdulteration(Vol. 1, p. 218), by Otto Hehner. This article is about as long as 50 pages of this Guide. There is an interesting historical introduction, from which we learn that the first legal statute in which the adulteration of food is noticed dates from the reign of King John in England (1203). There is an elaborate account of all the subsequent legislation in Great Britain, the United States, and Germany. The effects upon digestion of the chemical preservatives mentioned above are shown in the light of the very latest investigations. There is a section on colouring matter in food, with information about harmless and harmful dyes; and the last part of the article considers adulteration as recently applied to the more important articles of food, such as milk (with tests for borax and formaldehyde), cream, butter, cheese, lard, oils, flour and bread, sugar, marmalade and jams, tea, coffee, cocoa and chocolate, wine, beer, spirits, non-alcoholic drinks, and vinegar.
The properties of adulterants and colouring matters are described in separate articles, such asGlucose(Vol. 12, p. 141);Saccharin(Vol. 23, p. 970);Paraffin(Vol. 20, p. 752), which is sometimes added to coffee when it is roasted;Alum(Vol. 1, p. 766), often used with weak and unstable flours in bread making, and unwholesome, although not strictly speaking an adulterant;Sago(Vol. 23, p. 1003) andArrowroot(Vol. 2, p. 649), which provide adulterants of cocoa;Chicory(Vol. 6, p. 131), which many consumers insist upon using in their coffee;Copper,Compounds(Vol. 7, p. 109), which describes the copper salts used for colouring canned vegetables;Anatto(Vol. 1, p. 943) andTurmeric(Vol. 27, p. 474), two harmless vegetable colouring matters, much employed; andAniline(Vol. 2, p. 47). A full list of the various other colouring matters will be found in the articleDyeing(Vol. 8, p. 744).
Another group of articles will be found particularly useful in connection with the manufacture of certain classes of food products. Among these areFermentation(Vol. 10, p. 275), by J. L. Baker, the noted English analytical and consulting chemist;Fungi(Vol. 11, p. 333), illustrated, with its information about molds;Bacteriology(Vol. 3, p. 156), illustrated, especially for the material relating to the nature of toxins (p. 174)—both of these articles by the late Professor Ward of Cambridge and Professor Blackman of the University of Leeds;Medical Jurisprudence,Food Poisoning(Vol. 18, p. 29), by Prof. H. H. Littlejohn, of the University of Edinburgh, and T. A. Ingram; andPoison(Vol. 21, p. 893), by the late Dr. Sir Thomas Stevenson, of Guy’s Hospital, London.
The diseases of animals which affect meat are described in the articleVeterinaryScience(Vol. 28, p. 2), by George Fleming, author ofAnimal Plagues, and Prof. John MacQueen of the London Veterinary College, which contains sections on diseases of cattle, sheep and pigs as well as on the principal parasites of domestic animals; and there are separate articles onAnthrax(Vol. 2, p. 106);Foot and Mouth Disease(Vol. 10, p. 617),Pleuro-Pneumonia, orLung Plague(Vol. 21, p. 838), andRinderpest(Vol. 23, p. 348).