I RAW MATERIALS AND PRIMITIVE MANUFACTURES 5 



the disagreement of Vinegar and Nitre is mentioned, for 

 supposing the words to be rightly translated .... it seems 

 very hard to find what show of Antipathy there is between 

 Vinegar, and the Saltpetre that is commonly sold in our 

 shops for Nitre ; wherefore strongly presuming that Solomon 

 .... made use of Egyptian Nitre .... when once I 

 received the Nitre that I have mentioned, and saw it in signs 

 of an Alcalizate nature, I quickly poured upon it some strong 

 Vinegar, and found as I expected that there presently ensued 

 a manifest conflict, with noise, and store of bubbles, with 

 which Experiment I afterwards acquainted some Critics, 

 and other learned men who were not ill-pleased with it " 

 (Experiments and Notes about the Produdbleness of Chymical 

 Principles, 1680, p. 30; Works, 

 1725, III. 371). 



SALTPETRE or NITRE (Fig. 2), 

 a salt-like substance formed 

 by the decay of animal matter 

 and found as an incrustation 

 in the neighbourhood of 

 stables, was introduced into 

 Europe from the East. SAL- 

 AMMONIAC (Fig. 3), a salt of 

 similar origin, was manufac- FIG. 4 -T H E COI.ENSO DIAMOND 



ill,- i) j British Museum (Natural History) 



tured by heating camels dung ; 



it differed from other salt-like substances in that it could 

 be vaporised completely by gentle heat. The name was first 

 applied to a mixture of common salt and soda found near 

 the temple of Jupiter Ammon in Upper Egypt, but was 

 transferred by the early alchemists to the volatile salt just 

 referred to. 



Earths and rocks. A number of other substances, which 

 may be classed together as earths or rocks, were employed 

 for various purposes. FULLER'S EARTH, a white, friable clay, 

 was used as a cleansing agent prior to the manufacture 

 of soap. CHALK, LIMESTONE, and MARBLE were employed 



