196 PHILOSOPHICAL TRANSACTIONS. [aNNO 1792. 



that the death of the 2 masters was to be imputed to their peculiar position on 

 the wreck.. Exposed to heavy showers of sleet and snow, they might suffer from 

 being wet with fresh, rather than salt water: they might also suffer from being ex- 

 posed to the cold of the atmosphere, probably 7 or 8 degrees greater than that of 

 the sea. The chilling effects of evaporation might operate against them, promo- 

 ted as these must have been by the high wind; or they might receive injury from 

 their frequent immersions in the sea, producing an alternation in the media sur- 

 rounding. This last supposition did not indeed strike me at this time; the others 

 dwelt on my mind. 



Of the powers attending animation, that which seems fundamental, is the ca- 

 pacity of the living body of preserving the same heat in various degrees of tempe- 

 rature of the same medium, and indeed in media of very different densitv and 

 pressure. If a definition of life were required, it is on this faculty that it might 

 best be founded. It is known that some fluids, applied to the skin, vary in their 

 effects according to their impregnation. In the same degree of temperature, pure 

 water on the surface of the body is much more hurtful than water in which salt is 

 dissolved. Seafaring men are universally acquainted with this, and a striking proof 

 of the truth, as well as of the importance of the observation, may be found in 

 the Narrative of Lieut. Bligh. Probably the saline impregnation may stimulate 

 the vessels of the skin in some way that counteracts the sedative or debilitating 

 action of the cold. At any rate, it seemed not unlikely that some light might be 

 thrown on this curious subject, by observing the effects of immersion in fresh 

 and salt water, of equal temperature, on the animal heat. And this might also 

 assist in accounting for the death of the unfortunate men already mentioned. 



Exper. 1. I placed a large vessel, containing 170 gallons of salt water, in the 

 open air. The atmosphere was damp, and what is called raw. The thermometer 

 stood at 44° in the air, and this also was the temperature of the water. The 

 subject of my experiment was Richard Edwards, a healthy man, 28 years of age, 

 with black hair, and a ruddy complexion. The hour chosen for his immersion 

 was 4 in the afternoon, about 2 hours after his dinner; a time appointed rather 

 for my own convenience, than as being most proper for the purpose. His heat 

 was 98° before undressing, his pulse 100 in the minute. He was undressed in 

 a room where the mercury was at 56°; and afterwards stood naked before the 

 fire till his heat and pulse were examined again, and found as before. He then 

 walked pretty briskly through a flagged passage into an open court, where the 

 north-east wind blew sharply on him : he was exposed to it for a minute, and 

 then plunged suddenly into the water up to the shoulders. The thermometer, 

 which had been kept in a jug of warm water, at the heat of 100°, was intro- 

 duced into his mouth, with the bulb under his tongue, as soon as the convulsive 

 sobbings occasioned by the shock were over. The mercury fell rapidly, and a 



