On preserving Fresh Water sweet . 61 
that the water of these tanks was contaminated before it 
was put into them ; for in fact the whole of the water was 
brought on board in casks for the purpose of filling the 
tanks, and no particular care was taken to taste the water 
at the time of taking it on board. 
After the water, kept in this manner, had remained on 
board a length of time which was deemed sufficient for 
experiment, it was used out, and the tanks were replen- 
ished as occasion required: but in some of the tanks, on 
board one ship at least, the original water had remained 
three years and a half, as appears by the certificates here- 
with inclosed. About twenty-five gallons of the water, 
which had remained this length of time in the ship, are 
sent to the Society, in two vessels made of the same sort 
of tinned copper with which the tanks were lined. I 
am, &c. 
Samuel Bentham. 
Mr. Taylor. 
A certificate from captain William Bolton, command- 
er of the said vessel, dated Sheerness, S8th of June 1800, 
accompanied this letter, stating, that the water delivered 
to the Society was taken from a tank holding about seven 
hundred gallons, and which his predecessor, captain 
Portlock, had informed him had been poured into this 
tank in December 1796, except about thirty gallons add- 
ed in 1798, and had remained good during the whole 
time. 
The signatures to the above accounts were certified on 
the 28th of June 1800, by the reverend C. Thee, minis 
ter of Sheerness. 
In a letter dated January 27 , general Bentham also 
states, that the water which had been preserved sweet on 
board his majesty’s sloops Arrow and Dart, and of which 
he had sent specimens to the Society, was taken from the 
