On prefervhig FreJJj Water Jkueet. 13 



fliould not be a6led upon by the water, fo as to become a 

 caufe of contamination. Accordl/igly, on board the two 

 Ihips here alluded to, the ereater part of the water was kept, 

 not in cafks, but in cafes or tanks, which, though they were 

 made of wood, on account of Urength, were lined with me- 

 tallic plates, of the kind manufai^hired by Mr. Charles 

 Wyatt, of Bridge-ftreet, under the denomination of tinned 

 copper-flieets ; and the junfturcs of the plates or (heels were 

 foldcrcd- together, fo that the tightncfs of the cafes depended 

 entirely on the lining, the water having no where accefs to 

 the wood. The Ihape of thefe cafes was adapted to that of 

 the hold of the Ihip, iome of them being made to (it clofe 

 under the platform, by which means the quantity of water 

 flowed was confiderabiy greater than could have been ("towed, 

 in the fame fpacc, bv means of calks ; and thereby the ftcnv* 

 age room on board (hip was very much increafed. 



The quantity of water kept in this manner on board each 

 fliip was about forty tons, divided into (ixteen taiiks ; and 

 there was likewife on board each of the fliips about thirty 

 tons flowed in ca(ks as ufual. 



As the flowing the water in tanks was conlidered as an 

 experiment, the water in the cafks was ufed in preference j 

 that in the tanks being referved for occa(ions of neceflity, 

 excepting that a fmall quantity of it was u(ed occafionally for 

 the purpofe of afcerlainlng its puritv, or when the water in 

 the cafks was deemed, when compared with that in the 

 tanks, too bad for ufe. 



The water in thirteen of the tanks on board one fliip, and 

 in all the tanks on board the other, was aKva\'s as fweet as 

 when firft taken from the fource ; but in the other three of 

 the tanks, on board one fliip, the water was found to be 

 nacre or lefs tainted as in the cafks. This difference, how- 

 ever, is ealily accounted for, by fuppofing that the water of 

 thefe tanks was contaminated before it was put into them j 

 tor in faiSl the whole of tlie water was brought on board in 

 cafks for the purpofe of (illing the tanks, and no particular' 

 care was taken to taltc the waier at the time of taking it on 

 board. 



After the water, kept in this mariner, had remained on 

 board a length of time which was deemed fufhcient tor expe- 

 riment, it was ufed out, and the tanks were rcploniflicd as 

 tjccafion required : but in fomc of the tanks, on board one 

 iliip at lead, the origitial wattr had remained three years aiid 

 a h^lf, as appears by the certificates herewith inclofed. About 

 twenty-five gallons of the water, which had remained this 

 length of time in the fl>ip, are li nl to the Society, in two vef- 



