THE TECHNOLOGIST. [June 1, 1864. 



500 ON GRANITE AND ITS USES. 



of jelly," as a very visible, tangible, and withal beautiful solid. Yet 

 think of that other most sad use of the word as applied to the utter 

 annihilation of the perfection and beauty of a sensitive, living, graceful 

 human body, when it is spoken of as the victim of some railway 

 collision, or other terrihle catastrophe, and is described as having been 

 crushed or beaten into a jelly. "We know that it retains a shape, but one 

 so ill-defined that we speak of it as shapeless. In the same sense, the 

 endlessly altering, undulating sea-Medusee are popularly called jelly- 

 fishes. 



The other familiar amorphous bodies which I might name are, on 

 the one hand, such soft substances as the curd of milk, the boiled white 

 of egg, or clay in its plastic state as used by the potter and the sculptor ; 

 and on the other, such shapeless hard masses as flints or other silicious 

 pebbles. In their internal structure, the softer of those bodies have an 

 arrangement of particles approaching in mobility and unfixity to that of 

 liquids ; and the harder of the amorphous bodies exhibit none of the 

 distinctive properties of crystals, and may be compared to congealed or 

 rather coagulated jellies. 



The only everyday English word which I have been able to think of 

 as expressive of this formless form of matter is one which, from its 

 associations, is perhaps not a very welcome one — namely, the word 

 " clot." Clotted (or clouted) cream has no unpleasant associations with 

 it, but one cannot say the same of clotted blood. Both, however, convey 

 the same idea of vaguely consolidated substance ; and I do not know a 

 more significant phrase for solid sense apparently jumbled, till it has 

 seemingly lost, though in reality it retains solidity, than the words of an 

 old writer, applied by a reviewer of Thomas Carlyle to his ' Sartor 

 Eesartus,' as a book consisting of " clotted nonsense." The amorphous, 

 curdled, or clotted condition, is as alien to the Useful properties of glass 

 as the crystallised one. 



What, then, is the glassy shape or structure ? It is a compromise 

 between the crystalline and the amorphous one. Glass reflects and 

 transmits light as a crystal does, but without necessarily doubly refracting 

 or polarising it. It does not break into flat-faced, sharp-cornered solids 

 like a crystal, but into curved or hollowed pieces, scooped out like 

 shells ; and when struck, as with a hammer, or allowed to fall, it is 

 fractured into all kinds of curvilinear solids without shattering into 

 acute-angled fragments or keen-edged grains. 



You may be disposed to say that broken glass is sharp and cutting 

 enough ; and so, no doubt, it is, especially when the glass was originally 

 thin ; but look at the relics of a broken tumbler not deliberately ground 

 to powder, and you will see that the sharpest pieces are rounded in their 

 fracture. I have in my possession part of a glass air-pump receiver, 

 crushed in by the pressure of the atmosphere ; part of a soda-water glass 

 machine, blown to pieces in my class-room ; as well as the fragments of 

 a glass basin, which spontaneously split in two. All display the same 



