1816.} Scientific Intelligence. 469 
I beg leave to inform you that I have one in my possession that has 
been made near 20 years since, which you may inspect at any time. 
Lam, Sir, your most obedient humble servant, 
182, Strand, Apri! 13, 1816. H. Cary. 
IV. Fermenting Heat.—Steam. 
(To Dr, Thomson.) 
SIR 
> 
It is well established that a degree of moisture is essential to the 
fermentation of vegetable matter, and also an elevation of tempe- 
rature above the freezing point. About 60° of Fahrenheit’s scale 
is considered favourable for many common processes in the arts; 
but 1 am not aware that it has been determined at what higher 
degree fermentation would be checked, and what still farther 
augmentation of temperature would entirely arrest its progress. in 
summer time good housewives frequently preserve milk from ‘¢ turn- 
ing sour,” and also their conserves, by scalding. It is of import- 
ance to ascertain this augmentation of temperature exactly, parti- 
cularly with regard to the operations for deoxidizing indigo. You 
will allow me, therefore, to make the inguiry. At the same time 
permit me to ask if it has been determined what degree of pressure 
has been found most economical and advantageous in the employ- 
ment of steam, to work that grand but expensive instrument, the 
steam-engine ? Your obliged, 
cC—, sprit 9, A. M. 
V. On the Pavement of London. 
(To Dr, Thomson.) 
DEAR SIR, 
The bad state of the pavement in almost every street in London 
and Westminster where carriages of great burden are in the habit 
of going, cannot but be visible toevery person who pays the slightest 
attention to the streets. It is a subject, I believe, which has lately 
engaged the particular attention of several public bodies, and may 
not be unworthy of a place in your Annals. , 
On passing the workmen now employed in paving that part of 
the Strand just beyond Somerset House, 1 observed that the stones 
were all shaped like wedges, having the narrower extremity down- 
wards, Viz. :— 
a * 
» Tam not informed upon what principle this is done, but, accord- 
ing to my ideas, it does not appear to be the best method of 
securing the uniformity, or preserving the strength, of the paves 
