tools used in measuring and weighing, as an aid to vision,12.Sea,battering action of the,140;coast ever changing,385,386;effect of volcanic eruptions on the,299;floor deposits of the, affected by volcanoes,360,361;in receipt of organic and mineral matter,359;hot and cold currents of the,102;littoral zone of the,351,352;puss,142;rich in organic life,352,353;solvent action of the,361;strata, formation of,354;water, minerals in,185;weeds,155,156.Seas, dead,originally living lakes,200;water of, buoyant,199;eventually the seat of salt deposits,199-201;general statement as to division of,83,84;shape of the,83,84.Seashore, air of the,98.Seasons, changing the character of the,61,62.Sense of hearing,9,10;of sight,10;of smell,9,10;of taste,9,10;of touch,9,10.Seracs,214.Shocks, earthquake. See underEarthquakes.Shore lines, variation of,83,84.Shores, cliff,138-142.Sink holes,202;in limestone districts,253,254.Skaptar,eruption of,297,298;lava from the eruption of,298.Sky, mackerel,35.Snow,207-225,244;as an evidence of atmosphere,65;blankets, early flowers beginning to blossom under,208;covering, difference between an annual and perennial,210;effect of, on plants,208;electrical action in the formation of rain and,164;flakes, formation of,164;red,210;slides,210;slides, phenomena of,210,211.Soil,alluvial,321,322;atmospheric circulation of,330,331;conditions leading to formation of,313,331;continuous motion of the,314;covering of the earth,343;decay of the,314,315;degradation of the,344-348;means for correcting,346-348;destruction in grain fields greater than the accumulation,344;developing on lava and ashes an interesting study,343;development of, in desert regions,340;effect of animals and plants on the,317-320;effect of earthquakes on the,375;fertility of the, distinguished from the coating,344,345;fertility of, affected by rain,327;formation of,314-321;glacial, characteristics of,324;glaciated,323,324;irrigation of the,328-330;local variation of,327;mineral,321;of arid regions fertile when subjected to irrigation,341;of dust or blown sand,321;of immediate derivation,321,322;phenomena,313;processes of organic life in the,315;variation in,321-331;vegetation protecting the,316,317;washing away of the,346,347;winning, from the sea,337;work of ants on the,318;tiller, duty of the,348.Solar bodies,general conditions of the,63-71;forces, action of, on the earth,349;system,52,56;independent from the fixed stars system,43;original vapour of,52,53;singular features of our,68;tide,127.Spheres,difference in magnitude of,51;motions of the,50,51;planetary, rotation of, on their axes,56.Spots, sun,72.Spouting horn,141.Springs, formation of small,252.Stalactitization,256.Stalagmites and stalactites on the roof and floor of a cavern,257.Stars as dark bodies in the heavens,47;discovery of Fraunhofer and others on,23,38;double,39;and tidal action,131;earliest study of,10;fixed, important observations by the ancients of planets and,43;not isolated suns,38,39;variation in the light of,46;limit of, seen by the naked eye,11;revolution of one star about another,46,47;shooting,47;speed of certain,51;study of,31-80;sudden flashing forth of, due to catastrophe,46;voyage through the,44,45;star, wandering,74.Stellar realm,31-80.Storms,circular,111;desert,121,122;expansion of air contained in a hollow wall during the passage of,114;great principle of,105,106;in the Sahara,121;lightning, more frequent in summer,167;paths of,115;secondary, of cyclones,112;spinning,115;thunder,165-167;whirling,106,124;whirling peculiarity of,108,109.Strabo, writings of,18.Sun,atmosphere of the,73;constitution of the,72;distance of the earth from the,29;effect from changes in the, and earth,59;envelope of the,73,74,97;experiments illustrating consolidation of disseminated materials of planets and,40;finally, dark and cold,42;formation of the eight planets of the,53;heat leaving the,41;heat of the,76;imaginary journey from the, into space,44;mass of the,76,77;path of the earth around the,55;physical condition of the,71;Prof. Newcomb's belief regarding the heat of the,52;spots,75;abundant at certain intervals,72;difficulty in revealing cause of,75;structure of the, a problem before the use of the telescope,72;table of relative masses of, and planets,77;three stages in the history of the,71;tides,126;why does it not act in the same manner as the moon?78.Surfaces, level,90.Surf belt, swayings of the,137.Swamps,diagram showing remains of,335;Dismal Swamp,95,333;drainage of,334,335;fresh-water,334,335;phenomena of,167,168.Table-lands,91.Table of relative masses of sun and planets,77.Telescopes,11,12,45;first results of,72;power of,11;revelations of,45.Temperature,effects of, produced by vibration,42;in the doldrum belt,118;of North America,118;of the Atlantic Ocean,118.Tempests, rate of,99,100.Thunder,166;more pronounced in the mountains,166.Thunderstorms,165,166;distribution of,166,167.Tidal action,recent studies of,131,132;marshes of North America,340.Tides,carving channels,129;effecting the earth's rotation,130;effect of, on marine life,130;height of,128,129;moon and sun,126,127;normal run of the,127;production of,131;of the trade winds,150;solar,127;travelling of,127,128.Tillage introducing air into the pores of the soil,331.Tornadoes,112,113,317;development of,113;effect of, on buildings,113;fiercest in North America,113;length of,115;resemblance of, to hurricanes,115;upsucking action of,114,115.Torrents,177-179,204.Trade winds. See underWinds.Training in language,diminishing visual memory,401;soldiers to measure distances,28;to measure intervals of time,28;for a naturalist,25-29.Tunnels, natural,257.Uranus,70.Valley of Val del Bove formed from disturbances of Mount Ætna,294.Valleys,diversity in the form of river,188-191;river,193.Vapour,156,157,159,163;gravitative attraction of,34,35;nebular theory of,52,53;original, of the solar system,52,53.Vegetation,and dew,160;in a measure, independent of rain,160;protecting the soil,316,317.Vein, diagram of a,260.Venus,64,78;recent observations of, by Mr. Percival Lowell,64.Vesuvian system, study of the,285.Vesuvius. SeeMount Vesuvius.Visualizing memories,402,403.Volcanic action,268-276.Volcanic eruption ofa.d.79,288;important facts concerning,276-279;islands,272;lava a primary feature in,266;observations of, made from a balloon,301;peaks along the floor of the sea,272,273;possibility of throwing matter beyond control of gravitative energy,300.Volcanoes,125,203,263;abounding on the sea floor,302;accidents from eruptions of,288;along the Pacific coast,271;ash showers of, maintaining fertility of the soil,289;distribution of,271;eruption of,286-294,368;explosions from, coming from a supposed liquid interior of the earth,275;exporting earth material,310;little water,375;Italian, considered collectively,296,297;Neapolitan eruptions of and the history of civilization,288;subsidence of the earth after eruption of,287,291;origin of,263-274;phenomena of,263-267;submarine,301;travelling of ejections from,287,288.Waters,crevice,250;of the earth,250,251;cutting action of,117,192;drift, from the poles,151;journey of, from the Arctic Circle to the tropics,151,152;dynamic value of,171;expansion of, in rocks,270;geological work of,168-206;in air,99;of the clouds usually frozen,207;pure, no power for cutting rocks,204;rock,250,263;sea, minerals in,185;store of the earth,125;system of,125,156;tropical,151;velocity of the, under the equator,150;wearing away rocks,178,179;underground, carrying mineral matter to the sea,193;chemical changes of, leading to changes in rock material,262,263;effect of carbonic-acid gas on,251;operations of the,126;wearing away rocks,178,179;work of,250.Waterfalls,189-193;cause of,191;the Yosemite,192;Niagara,191,192;numerous in the torrent district of rivers,192;produced by dikes,192;valuable to manufactures,192,193.Waterspouts,115,116;atmospheric cause of,116;firing at,116;life of a,116;picturesqueness of,116;the water of fresh,117.Waves,128,129,132,145;action of friction on,135,136;break of the,136;endurance of sand against the,145;force of,133,136,139;marine, caused by earthquakes,387;of earthquakes,389;peculiar features in the action of,137;size of,137,138;stroke of the,144;surf,135;tidal height of,132;undulations of,132;wind,132;wind influence of, on the sea,134,135;wind-made,128.Ways and means of studying Nature,9.Weeds of the sea,155.Well, artesian,258,259.Whirling of fluids and gas,36,37.Whirlwinds in Sahara,121.Will-o'-the-wisp,167.Winds,101,110,122,317;effect of sand,122;hurricane,110;illustration of how they are produced,101;in Martha's Vineyard,120;of the forests, work of the,317;of tornadoes, effect of,113;on the island of Jamaica,119,120;regimen of the,119;variable falling away in the nighttime,100;trade,102-105;145,146,150;action of, on ocean currents,145:affected by motion of the earth,103;belt, motion of the ocean in,146;flow and counter-flow of the,150;tide of the,150;uniform condition of the,102;waves, work of,132,134,135.Witchcraft, belief of, in the early ages,21.Zoölogy, rapid advance in,14,15.