124 IMPROVEMENTS IN THE MANUFACTURE OP GAS. 
lent to Lowe's patent scrubber, now used by the Chartered 
Gas Company. The steaming, condensing, and naphthaUz- 
ing processes are adopted at the gas-works in Brick Lane, 
having been patented by Mr. Lowe in 1832. The blast of 
air claimed by Mr. Palmer was introduced some years ago 
in Hull by Mr. Malam. The process of naphthalizing gas 
has long been known and employed Some years ago, it 
was described at one of the Friday evening meetings at the 
Royal Institution. We must therefore throw aside the im- 
pression that the advantages of Mr. Palmer's patent are 
confined to the works of the Western Gas Company, the 
most important parts of the process being already either 
employed at other works, or superseded by modifications 
answering the same purpose. 
The chemical certificate must not be received^as conclu- 
sive evidence of the uniform superiority of the gas to be 
furnished by the new company, for this certificate states, 
that ''the gas furnished by different companies varies 
generally in illuminating power, as does that supplied by 
the same company at different times." It is well known, 
however, that one of the main difficulties in the manufac- 
ture of gas consists in the production of an equable and 
uniform product, the result being affected by variations in 
the temperature employed, and by other circumstances 
connected with the manipulation. The certificate, therefore, 
may be taken as evidence of the value and purity of a 
sample of gas produced for the express purpose of ex- 
amination ; further than this no dependence can be placed 
on it. The illuminating power of gas depends, in a great 
measure, on the proportion of carbon it contains, and its 
purity can be effected by various processes well known and 
often practised. It would be easy for any company to fur- 
nish, from ordinary coal, a sample of gas equal in every re- 
spect to that above described. It remains to be shown 
whether any company will continue to bestow the same 
