388 RELATIVE ATTRACTIONS OF 
to be at much additional expense in concentrating 
it when removed fom the chambers. 
Having explained my views to a friend, he, 
during the last winter, and when his chambers 
were not working well in consequence of the 
severe cold, had a vessel of water so placed in the 
furnace as that the hot gases were enabled to 
convey along with them into the chambers a com- 
paratively large quantity of vapour: and this plan 
cannot but have been attended with some benefit ; 
yet, the benefit must have been highly inadequate, 
because, as in the case of steam turned in from a 
pipe, the vapour thus admitted would be speedily 
condensed by the cold chambers. 
It is quite evident that the great desideratum 
is to be enabled to give the whole interior of the 
chambers, at all times, a temperature not less 
than that of summer; nor do I think that a doubt 
can reasonably be entertained that a temperature 
considerably higher than the maximum tempera- 
ture of summer would be attended with a cor- 
responding beneficial effect. Consequently, what 
I suggest as an improvement in the working of sul- 
phuric acid chambers, is that leaden pipes should 
be caused so to pass through the interior of the 
chambers as that when the steam of boiling water 
