182 



CHEMISTRY AND ALCHEMY. 



Bacon (Fig. 130), called the Admirable Doctor, who had a narrow escape of 

 paying with his life the crime of being in advance of his age. He passed 

 part of his life in prison. Sal vino degli Annati had just invented a new 

 process for making glass of a lenticular shape, and Bacon took up this 

 invention, and, having perfected it, made achromatic glasses and the 

 telescope, thus opening the immensities of the sky to future astronomers. 

 He discovered a combustible substance similar to phosphorus, and with 

 saltpetre, which had hitherto only been used medicinally, he composed 



Fig. 129. The Miner. Designed and engraved in the Sixteenth Century by J. Amman. 



gunpowder. There is no truth in the story of his having been the first 

 victim of his own discovery ; for, though he did not foresee the tremendous 

 consequences arising out of the manufacture of this inflammable mixture, 

 he had assumed that it would bring about a revolution in the art of 

 war. The melting of bells, practised as early as the thirteenth century, 

 suggested the idea of casting cannon (Fig. 131). Roger Bacon had 

 investigated all the sciences, and yet, upon his death-bed, he bitterly 

 exclaimed, " I repent of having laboured so much in the interest of science." 

 Thus from the beginning of the fourteenth century, France, Germany, 



