SCIENCE, INVENTION, DISCOVERY. 



325 



the linings of small furnaces, and in the 

 process of electrotyping. It is unctuous to 

 the touch and. has a high metallic luster, and 

 is used also in polishing and lubricating com- 

 pounds, but for this latter purpose has been 

 found too hard to be satisfactory. 



Grapliophone. This instrument is, iu 

 its essential features, identical with Edison's 

 phonograph. [See Phonograph.^ The grapho- 

 phone now in experimental use is the inven- 

 tion of Mr. Sumner Tainter, aided by Professor 

 Bell. In a correct nomenclature the phono- 

 graph would represent a machine for making a 

 record of speech, the record made would be 

 termed a phonogram, and the graphophone 

 would be a machine for reproducing speech from 

 the phonogram. The words are all derived from 

 the same two Greek roots, which mean ' ' write ' ' 

 and " speak." 



Gravitation, as a supposed innate power, 

 was noticed by the Greeks, and also by Sen- 

 eca, who speaks of the moon attracting the 

 waters, about 38 A. D. Kepler investigated 

 the subject about 1615 ; and Hooke devised a 

 system of gravitation about 1674. The prin- 

 ciples of gravity were demonstrated by Galileo, 

 at Florence, about 1633 ; but the great law 

 on this subject, laid down by Newton in his 

 Principia, in 1687, is said to have been proved 

 by him, in 1670. His attention was directed 

 to the subject by the fall of an apple from a 

 tree, in 1666. In 1867, M. Chasleslaid before 

 the Paris Academy of Sciences some letters al- 

 leged to have been written by Newton to Pas- 

 cal and others tending to show that to Pascal 

 was due the theory of gravitation. The au- 

 thenticity of these letters was denied and their 

 forgery afterward shown. 



Guillotine, the instrument of decapitation 

 was introduced during the French Revolution 

 by the Convention, and named after its sup- 

 posed inventor, Joseph Ignace Guillotin, a 

 physician, who, however, was only the person 

 who first proposed its adoption. It was erected 

 and first employed to execute a highwayman 

 on the Place de Greve, Paris, 25th April, 1792. 

 It is composed of t'wo upright posts, grooved on 

 the inside, ajid connected at the top by a cross- 

 beam. In these grooves a sharp iron blade, 

 having its edge" cut obliquely, descends by its 

 own weight on the neck of the victim, who is 

 bound to a board laid below. 



Gun-Barrels. The finest musket-bar- 

 rels are made of iron which contains a portion 

 of steel, or undergoes some steeling process. 

 Laminated, twisted, or Damascus steel is used 

 in the manufacture of the best barrels. Scraps 

 of saws, steel pens, files, springs, and steel 

 tools are collected from variousworkshops, for 

 the material of laminated steel. These are 



\ cut in small and nearly equal pieces, cleansed 

 and polished by revolving in a cylinder, fused 

 into a serni-fluid state, and gathered into a 

 ' ' bloom ' ' or mass. This bloom is forged with 

 a three-ton hammer, and hardened and solidi- 

 fied with a tilt-hammer. It is then rolled into 

 rods, each rod is cut into pieces six inches 

 long, and these pieces are welded together. 

 The rolling, cutting, and welding process is 

 then repeated several times, and thus finally 

 the metal is brought into a very hard, tough, 

 fibrous, and uniform state. Twisted steel foi 

 barrels is made by taking thin plates of iron 

 and steel, laying them alternately one on an- 

 other in a pile, welding them by heat and 

 hammering, and twisting them by very power- 

 ful mechanical agency until there are twelve or 

 fourteen complete turns to an inch. The 

 length becomes reduced one half and the thick- 

 ness doubled by this twisting. Barrels made 

 of Damascus steel are manufactured of steel 

 which has undergone a still further series of 

 welding and twisting operations. Some bar- 

 rels are made of a mixture of old files with old 

 horseshoe nails ; these are called stub Damas- 

 cus barrels. The files are heated, cooled in 

 water, broken with hammers, and pounded in 

 a mortar into small fragments. Three parts of 

 these fragments are mixed with five of stub 

 and the mixture is fused, forged, rolled, and 

 twisted. An inferior kind of Damascus twist 

 is made by interlaying scraps of sheet iron 

 with charcoal and producing an appearance of 

 twist, but without the proper qualities. Infe- 

 rior kinds of barrel-iron are known as " three- 

 penny-skelp " and "twopenny skelp " ; but 

 the worst of all is "sham-dam skelp." The 

 finest barrels are all twisted in form. The 

 skelps, or lengths of prepared steel, are twisted 

 into a close spiral a few inches long ; several 

 of these spirals are welded end to end, and the 

 fissures are closed up by heating and hammer- 

 ing. The rough barrel, with a core or man- 

 drel temporarily thrust in it, is placed in a 

 groove and hammered cold until the metal be- 

 comes very dense, close, strong, and elastic. 

 The interior is then bored truly cylindrical by 

 a nicely adjusted rotating cutting tool. If, on 

 close inspection, the interior is found to be 

 straight and regular, the exterior is then 

 ground on a rapidly revolving stone and finally 

 turned in a lathe. The skelps for the com- 

 moner barrels are heated, laid in a semi-cylin- 

 drical groove, hammered until they assume the 

 form of that groove, placed two and two to- 

 gether, and heated and hammered until one bar- 

 rel is made from two halves. These are browned 

 externally with some kind of chemical stain. 

 The finest barrels are rubbed externally with 

 fine files and polished with steel burnishers. 



