286 



Inaccuracies in Todd's Edition 



is soluble by m^ans of sea-salt, but 

 is injured by no other salt, Sfc. 



Granite, a stone composed of se- 

 parate and very large concretions 

 radely compacted together ; and of 

 great hardness, ^c. 



Gypsum. Tlie name of a class of 

 fossils ; the. plaster stone ; white 

 lime ; a kind of plaster. 



Iron, a metal comtnon to all parts 

 of the world : though the lightest of 

 all metals, except tin, it is consider-f 

 ably the hardest, and, when pure, 

 naturally malleable, &c. It is the 

 only known substance that is at- 

 tracted by the loadstone. Iron has 

 greater medicinal virtues than any 

 of the other metals. 



Lime, matter of which mortar is 

 made. 



Manganese, is a name the glass- 

 men use for many different sub- 

 stances that have the same effect in 

 clearing the foul colour of their 

 glass ; it is properly an iron ore of a 

 poorer sort. 



Metal, a firm, heavy, and hard 

 substance, opaque, fusible, and mal- 

 leable. The metals are six in num- 

 ber : some have added mercury, or 

 quicksilver, to the number of the 

 metals, but as it wants malleability, 

 the criterion of the metals, it is more 

 properly ranked among the semi- 

 metals. 



heat ; volatile at a ver}- high tem- 

 perature ; soluble in nitro-muriatic 

 acid and in solution of chlorine, bttt 

 not in the other acids. 



Granite, a rock essentially com- 

 posed of quartz, feldspar, and mica, 

 in grains or crystals of various mag- 

 nitude. Its hardness and compact- 

 ness vary extremely. 



Gypsum, a compound of sulphuric 

 acid and lime, or native sulphate of 

 lime. "When heated red hot it loses 

 water of crystallization, and falls 

 into a white powder called plaster 

 of Paris. 



Iron, a metal found in most parts 

 of the world : its specific gravity is 

 778 water being 100, so that it is 

 not a heavy metal, though there 

 are many lighter. It is one of the 

 few metals which are magnetic. It 

 is employed in medicine, though of 

 much less importance than several 

 other metals. 



Lime, one of the alcaline earths, 

 lately shewn to be a metallic oxide : 

 it is an essential ingredient in mor- 

 tar and some other cements. 



Manganese, one of the metals. 

 The terra Manganese is often applied 

 to the native black oxide of this 

 metal, which is a commonly-occur- 

 ring ore. 



Metal. The metals are charac- 

 terized as a class, by a peculiar de- 

 gree of brilliancy and opacity ; they 

 are conductors of electricity and of 

 heat : they include the heaviest and 

 lightest solids, and differ extremely 

 in fusibility : some are brittle ; others 

 malleable and ductile. All the me- 

 tals unite to oxygen, producing me- 

 tallic oxides, which, combined with 

 acids, form metallic sails. The me- 

 tals at present known are forty-two 

 in number. 



