TECHNICAL CHEMISTRY. 321 



From what I have said, you will understand that in 

 a manufacture like that of sulphuric acid, where enormous 

 volumes of acid and deleterious gases have to be dealt with, 

 it is only by the careful application of scientific principles 

 that the process can be economically carried on, and carried 

 on so as not to be a nuisance to the neighbourhood. In all 

 the works which are scientifically conducted we not only 

 find the Glover and Gay-Lussac towers in proper action, 

 but we observe that the manager keeps a daily record of 

 the work of his chambers ; he ascertains moreover the 

 proportion of air and sulphur dioxide which enter his first 

 chamber, and the ratio of sulphur dioxide and nitrous fumes 

 which leave his last chamber, and thus he keeps a complete 

 hold over his process, and can tell at any moment when 

 anything goes wrong. The scientific vitriol manufacturer 

 too is a blessing instead of a curse to the district in which 

 his works are situated. The escape of noxious vapours from 

 a properly-managed sulphuric acid plant is inappreciable, 

 whilst the manufacture creates a demand for labour, and 

 becomes a source of income to hundreds of families. All 

 the more reason is there, then, that careless or ignorant 

 persons engaged in this trade should be compelled to adopt 

 the best and most perfect scientific methods of manu- 

 facture, and that the wasteful escapes of noxious vapours, 

 even too common at the present day, should be altogether 

 prevented. 



VOL. II. 



