300 LECTURES TO SCIENCE TEACHERS. 



same time the appliances, apparatus, and plant made use 

 of in the production of this most useful substance. This 

 is indeed all that any lecturer on Technical Chemistry can 

 with wisdom propose to do. The attempt to teach manu- 

 facturing by means of lectures is, on the face of it, one 

 which can only end in failure. But, on the other hand, 

 to apply the principles of chemical science to an industry, 

 and to explain the scientific basis upon which it rests, is not 

 only a legitimate, but a most necessary part of our national 

 system of scientific instruction, and one which ought by all 

 means and at all risks most strenuously to be encouraged. 

 For want of the general distribution of such a sound 

 knowledge of scientific principles amongst our manufacturing 

 and industrial population, the monetary loss to the nation, 

 to put the case in its lowest terms, has been, and even yet 

 is, enormous, and no portion of Government expenditure can 

 be so remunerative as that employed for the purpose of 

 spreading such a knowledge among the people ; thus 

 giving to manufacturers the means not only of conducting 

 their known processes with efficiency and economy, but, what 

 is even more important, enabling them to improve upon the 

 old system, to introduce new and better means of attaining 

 the end they have in view, and thus to bring about those 

 revolutions in manufacturing industries, with examples of 

 which the science of applied chemistry is so familiar. 



Let us then first turn our attention to the history of our 

 subject, and inquire when and how sulphuric acid became 

 first known and applied. It - appears probable that the 

 celebrated Arabian alchemist Geber, who is said to have 

 lived about the end of the eighth century, was acquainted 

 with sulphuric, or, as it was formerly called, vitriolic acid, 

 in an impure state. Basil Valentine, who lived in Erfurt 

 at the beginning of the fifteenth century, was the first to 

 describe fully the method of preparing* this acid from 

 ferrous sulphate or green vitriol, Fe S0 4 + H 2 0, and to point 

 out that when sulphur is burnt with nitre, a peculiar acid, 

 sulphuric acid, is formed. 



As its common name, oil of vitriol, indicates, this acid was 

 obtained in early times solely by the dry or destructive 

 distillation of green vitriol. This salt is first roasted in the 

 air, when it loses water, and becomes oxidized to a basic- 

 ferric sulphate, which can then be further heated in clay 



