THEIR HISTORY. 9 



K 



The Medisevalist workmen, in their scorn for the impossible 

 and love of surmounting difficulties, early endeavoured to over- 

 come the indomitable hardness and irrefragability of the Diamond, 

 and thereby to discover some means of cutting and polishing it the 

 same as other stones. Chemists likewise set to work to discover 

 its nature and to speculate on its origin. The consequent experi- 

 ments soon bore fruit, and in 1475 Louis de Berquem of Bruges 

 was able to cut three large Diamonds for Charles the Bold. Ber- 

 quem's invention consisted in the discovery that the Diamond 

 could be polished by means of its own dust, and consequently 

 could be ground away. His appliances were^ however, as may be 

 supposed, very inadequate for the task he undertook, and he suc- 

 ceeded in doing but little beyond polishing the natural facets of 

 the crystal, and so developing its brilliancy; succeeding lapidaries, 

 however, improved and perfected his method. About the end of 

 the 1 6th century, the art made great progress, and in the begin- 

 ning of the 17 th century the possibility of cleaving the Diamond 

 was discovered. This discovery was the most important step till 

 then made towards a thorough knowledge of the Diamond, but it 

 was not until more than a century after that its full value was recog- 

 nised. I shall refer, further on, more fully to this cleaving, but 

 may here state that the diamond-cutters of the 17th century found 

 they could split a diamond crystal in certain directions, which can 

 be done as easily and with as much certainty as one can split a 

 piece of slate, and availed themselves of this to divide a stone as 

 might be requisite for the improving of its shape or the removal of 

 defects. Scientific men, on their side, had not been idle, and 

 throughout the 17th century experiments were made by French 

 and Italian chemists as to the effect of heat on the Diamond, but 

 without result, and it was left for our own illustrious philosopher, 

 Sir Isaac Newton, to indicate for the first time the true nature of 

 the Diamond. 



Newton, in his investigation of the refraction of light by trans- 

 parent bodies, found that those that are uninflammable refract 

 light nearly in the ratio of their density, while those that are 

 inflammable have refractive powers that are greater than their den- 

 sity. And as the Diamond has a very high refractive power and a 

 comparatively low density, he concluded that it was combustible — 



