June 1, 1864.] THE TECHNOLOGIST. 



ON GRANITE AND ITS USES. 499 



All crystals more or less exhibit the same unity of structure. All 

 are crystals in the atom as well as crystals in the mass. Through their 

 height and depth and length and breadth, from their centre to their 

 circumference, they are crystals ; and you no more change their inner 

 and essential characters by changing their outer configuration, than you 

 change a yew-tree into a church steeple by cutting it into the shape of a 

 pyramid, or a box-tree into a bird by clipping it into the form of a peacock. 



The crystalline structure is one which the glass-maker dreads, 

 because the most important properties of glass are lost if it crystallise, 

 and it greatly tends to crystallise. Yet, strangely enough, it is not that 

 a crystal would not rival glass, for rock-crystal is better than glass for 

 lenses and prisms : it is that we cannot produce one mighty glass crystal, 

 out of which, like a great iceberg or ice-field, to saw windows, and 

 chisel goblets, and carve lamps and looking-glasses, lenses, and prisms. 

 We are in this respect like men to whom some hundred acorns have been 

 given, and who, if they had their will, would grow the hundreds into a 

 single mighty oak, out of which might be sawn logs fit to form in one piece 

 the keel or deck of a man-of-war, but who are compelled to accept a mere 

 copsewood of many trees, and, in despair of oak, build their ships of fir 

 and iron. 



When glass crystallises it does not do so in one clear mass, but shoots 

 up like an underwood into a forest of crystals ; and how incompatible 

 this arrangement is with the employment of glass as a transmitter of 

 light, any one may judge from the dimness of a window covered by a 

 tree-like crystallisation of frost. 



Glass, then, must not be crystalline. As little must it be amorphous. 

 This word " amorphous " is not a technical one, for which technology need 

 apologise ; but it is a scientific one, and I use it because I know no 

 everyday word which conveys its meaning. To speak of a solid body 

 which presents to our eyes a visible, conspicuous shape, and a well- 

 marked form, as shapeless and formless, seems on first consideration a 

 foolish and contradictory thing. It is like speaking of a shapeless shape. 

 Yet the language of poetry and the language of everyday life equally 

 acknowledge the necessity of thus characterising certain indefinable 

 forms. Thus Milton, in a famous passage of ' Paradise Lost,' describes 



Death as — 



' The other shape, 

 . . If shape it might be called, that shape had none 

 Distinguishable in member, joint, or limb ; 

 Or substance might be called that shadow seemed, 

 For each seemed either.' 



Here we have r the two essentials of amorphism, externally, vague out- 

 line, internally, vague structure. And if we at once descend from 

 poetical altitudes, we shall find in the homely word jelly the occurrence 

 of these amorphic essentials as fully recognised as in Milton's picture of 

 Death. All are familiar with what a cook or confectioner calls a " shape 



