TECHNICAL CHEMISTRY. 



BY PROFESSOR ROSCOE, F.R.S. 



LECTURE I. 



ON THE MANUFACTURE OF SULPHURIC ACID. 



IN his admirable Letters on Chemistry, Liebig gives it as 

 his opinion that the commercial prosperity of a country may 

 with great accuracy be estimated by the amount of sulphuric 

 acid it consumes. You will readily acknowledge this to be 

 true when you remember that there is scarcely an impor- 

 tant branch of industry which, directly or indirectly, does 

 not need to employ sulphuric acid for carrying on some of 

 its processes, and when you learn that the result of this 

 universal demand is that no less than 850,000 tons of 

 sulphuric acid were manufactured in Great Britain last 

 year, whilst this enormous amount is likely steadily to 

 increase. By far the largest portion of this acid is employed 

 in the manufacture, from common salt, of the alkali soda 

 in its different forms, the remainder serving to carry on 

 an endless variety of trades, amongst which those of the 

 artificial manure maker, the gold and silver refiner, the candle 

 maker, the dyer and bleacher, the calico printer, the lucifer- 

 match maker, the wire drawer, the galvaniser, and the 

 colour maker may be mentioned as some of the more 

 important. 



The national importance of this manufacture will now 

 be obvious to you, and I propose to point out, as clearly as 

 I am able, the chemical principles upon which this great 

 branch of chemical industry depends, describing at the 



