C S35 1 
provement of the fire-engine. This I prefented, with 
your letter, .to my worthy friend and relation, Mr. 
Carlifle Spedding, then fuperintendent of our coal- 
mines, who was an excellent mechanic, and had 
then the charge of five fire-engines, feveral of which 
had been under his care and management from the 
time, that thole machines were firfh brought into ufe, 
and had himfelf made confiderable improvements in 
them. He was pleafed to exprefs his approbation of 
what I had written, and was of opinion, that future 
improvements of the fire-engine muft depend chiefly 
on the right folution of thofe two propofitions, viz. 
“ To increafe the quantity of fleam from a given 
e£ vefiel and a given heat, by means of mechanical 
<c agitation •, and, to augment the elaftic force of a 
£< given quantity of fleam by means of fire:” and 
wifhed, that proper experiments could be made in 
thefe matters, which he thought would prove too 
expenfive for mofl private people. His untimely 
and much lamented death put an end to thefe en- 
quiries ; and a variety of necefiary avocations prevent- 
ed me from fooner communicating to you the refult 
of them. They are chiefly conjectures, which expe- 
rience muft ripen into ufe. 1 dare not afiert, that 
the theory is altogether faultlefsj therefore very un- 
fit to appear before the public. The honour you 
did me of communicating my rough plan of a hiflory 
of damps to the Royal Society, I efteem a parti- 
cular marks of your kindnefs and affeCtion 5 altho’ 
that plan was only intended for your own private ufe, 
and would not have appeared before that refpeCtable 
body, (efpecially in its prefent form) had it not 
Y y y 2 been 
