346 



THE CENTURY BOOK OF FACTS. 



portant undertaking, or the fortune of an 

 individual, was foretold by means of horo- 

 scopes representing the position of the stars 

 and planets. The system of the astrologers 

 was very complicated, and contained . regular 

 rules to guide the interpretation, so intricate 

 that years of study were required for their 

 mastery. Venus foretold love ; Mars, war ; 

 the Pleiades, storms at sea. Not only the 

 ignorant were the dupes of this system, Lord 

 Bacon believing in it most firmly. 



Pulley. The pulley, together with the 

 vise, and other mechanical instruments, is 

 said to have been invented by Archytas of 

 Tarentum, a disciple of Pythagoras, about 516 

 B. C. Ctesibius of Alexandria, architect and 

 mechanic, is said to have invented the pump, 

 with other hydraulic instruments, about 224 

 B.C., although the invention was ascribed to 

 Danaus, 1485 B. C. They were in general 

 use in England, A. D. 1425. The air pump 

 was invented by Otto Guericke in 1654. and 

 was improved by Boyle in 1657. 



Rainbow. A rainbow can only be seen 

 when the spectator stands between it and the 

 sun ; its center must always be directly oppo- 

 site the sun, moving with the sun's motion, 

 falling if , the sun is rising, and rising if the 

 sun is declining. A rainbow occurs when the 

 sun or moon, not too far above the horizon, 

 throws its beams upon a sheet of falling rain- 

 drops on the opposite side of the heavens. 

 Thus, a ray of light from the sun strikes a 

 rain-drop obliquely ; part of it is reflected at the 

 surface of the drop ; the rest, passing into 

 the drop, is refracted ; on the other side of 

 the drop part of the ray passes through, and the 

 rest is again reflected ; on passing from the 

 drop :~>n the same side that it entered, a second 

 refraction occurs. These successive reflections 

 and refractions separate the ray of white light 

 into its component colored rays, and as the 

 angles of incidence and emergence vary for 

 each color, the eye of a spectator perceives 

 them as distinct bands. Now, every drop in 

 the sheet of falling water which has equal 

 obliquity to the spectator's eye will send to it 

 rays of the same color. But the only drops 

 which can fulfill these conditions of like obliq- 

 uity of reflected rays are those which define the 

 base of a cone whose apex is the eye, and the 

 center of whose base is in a right line passing 

 through the sun and the eye of the spectator. 

 At or near, sunset, when the sun and the 

 observer are in the same horizontal plane, the 

 bow will be seen to form a complete semicircle ; 

 when the sun is higher in the sky, a smaller 

 arch is seen ; the entire circle could only be 

 visible to a spectator on the top of a very high 

 and narrow mountain peak, which would ele- 



vate his plane much above that of the sun's 

 rays without cutting off their light. A com- 

 plete circle may also be sometimes seen in the 

 rainbow formed by the sunlight on the spray 

 arising from cataracts. The lunar rainbow, 

 which is a comparatively rare but very beauti- 

 ful phenomenon, differs from the solar simply 

 in the source and intensity of the light by 

 which it is produced ; and, as in all cases of 

 feeble light, the distinction of the colors is 

 very difficult. In fact, except under the most 

 favorable circumstances, the lunar rainbows 

 rarely show colors at all, giving a pale, ghostly 

 gleam of apparently white or yellow light. 



Reaper, First in the United States. 

 In 1803 a reaping machine was patented by 

 Richard French and John J. Hawkins, but it 

 did not prove successful. Prior to 1832 there 

 were granted eight patents for machines for 

 cutting gi'ain. No inventor, however, suc- 

 ceeded in producing machines that possessed 

 sufficient practical merit to be used otherwise 

 than experimentally until we come to Bell, 

 Hussey, and McCormick, whose machines have 

 since become so well known . At the meeting of 

 the British Association at Dundee, September, 

 1867, the Reverend Patrick Bell stated that he 

 invented his reaping machine in 1826. Mc- 

 Cormick 's American machine was patented in 

 1834, and, with improvements added in 1845 

 and 1847, received a medal at the World's 

 Fair in London, 1851. In 1833, Obed Hussey, 

 then of Cincinnati. Ohio, patented a machine 

 to which he applied saw-toothed cutters and 

 guards. This machine was at once put into 

 practical operation, and gave general satisfac- 

 tion. Hussey, in 1847, patented the open- 

 topped slotted finger. The practical use of 

 self-rakers, in this country, dates from the in- 

 vention of W. H. Seymour of New York, in 

 1851. He arranged a quadrant-shaped plat- 

 form directly behind the cutters, a reel to 

 gather the grain, and a rake moving over the 

 platform in the arc of a circle depositing the 

 sheaves on the ground. In 1856. Owen Dorsey 

 of Maryland combined the reel and rake, and 

 his improvement has been extensively used 

 here and abroad, with some modifications, one 

 of which was by Johnston in 1865, who ar- 

 ranged it so that the size of the sheaves, or 

 gavels, as they are called, could be regulated 

 at the will of the driver. The names of 

 Haines, Ketchmn, Manny, and Wood are prom- 

 inent among inventors of improvements in 

 mowers and harvesters. 



Saddles. Pliny informs us that one Pele- 

 thronns was the first to introduce a piece of 

 leather fastened to the back of a horse for the 

 accommodation of its rider. For a long time 

 these cloths and pieces of leather were regarded 



