From Edward Nairne2
ALS: Historical Society of Pennsylvania
Cornhill March 19. 1770
When You did me the pleasure of calling on me last week, I mention’d to You that I had been trying to freeze water in which different quantities of Sea Salt had been dissolv’d, You then said You wish’d I had tasted the Ice, for it was thought to be fresh; At that time I had not tasted it, but since have tried the following Experiment; I took two ounces (averdupoise) of common Sea Salt and dissolv’d it in three pints and a half wine measure of Thames water, which I think is the proportion of Salt in Sea water according to Mr. Canton.3 I then put some of this salted water in a wide Stone dish about the depth of an inch and set it out on the leads, in hopes it woud be froze by morning, the next morning it was froze about the thickness of ½ an inch. I then took out the Ice and put it in a seive and wash’d it in a large Cistern of Thames Water, and afterwards let the water drain from it. Then I put the Ice in a Bason and kept it in a warm Room till it was dissolvd, and on tasting the dissolvd Ice I found it was so fresh, that if I had not put the Salt to the water my Self I Shoud not have suspected there had ever been a grain of Salt mixd with the water. I have sent You three Vials, in that markd A, is the dissolv’d Ice. In the Vial B is some of the same salted water that was not set out to freeze. In the Vial C is some of the water that was left in the dish that I took the Ice out of, (which appears to the taste to be considerably salter than that in the Vial B). I have tried the experiment twice and find the result exactly the same, the Thermometer out of doors between 7 and 8 o Clock Yesterday and this morning which were the times I washd the Ice was at 25 degrees of Farenheits. If You think this Experiment not conclusive Your objections would greatly oblidge Your most Obedient Humble Servant
P.S. The Salted water has been filtrated but the dissolvd Ice has not been filtrated.
To Dr. Franklin
Addressed: To / Dr: Franklin
2. The electrician and instrument-maker, an old acquaintance of BF; see above, X, 171 n. His letter is the first indication in these volumes that his experimental interests extended beyond electricity. But he had already acquired a transatlantic reputation, for at about this time he was elected, presumably at BF’s initiative, to membership in the APS. Thomas Coombe to his father, Sept. 11, 1770, Hist. Soc. of Pa.
3. For John Canton’s experiments on the compressibility of rain and sea water see above, XI, 245–6; XII, 220 n.