VOL. XXII. 3 rHILOSOPHICAL TRANSACTIONS. 575 



the space of 1 1406 ; therefore the rarefied oil was to the same expanded by the 

 heat of the human body, as 40 is to SQ ; by that of boiling water, as 15 to 14 ; 

 by that of tin beginning to cool, coagulate, and harden, as 15 to 13 ; and by 

 the heat of cooling tin when quite hardened, as 23 is to "20 ; the rarefaction of 

 air by an equal heat was 10 times greater than that of oil, and the rarefaction 

 of oil was 15 times greater than that of spirits of wine. From these data, put- 

 ting the degrees of the heat of the oil proportional to its rarefaction, and taking 

 12 parts for the heat of the human body, we then have the degree of the heat 

 of water when it begins to boil, viz. 33 parts, and when it boils more vehe- 

 mently 34 ; of tin when melted, or when it begins in cooling to harden, and 

 have the consistence of an amalgama, 72 parts, and in cooling is quite hard, 

 70 parts. 



Having discovered these things ; in order to investigate the rest, there was 

 heated a pretty thick piece of iron red-hot, which was taken out of the fire 

 with a pair of pincers, which were also red-hot, and laid in a cold place, where 

 the wind blew continually upon it, and putting on it particles of several metals, 

 and other fusible bodies, the time of its cooling was marked, till all the parti- 

 cles were hardened, and the heat of the iron was equal to the heat of the 

 human body ; then supposing that the excess of the degrees of the heat of the 

 iron, and the particles above the heat of the atmosphere, found by the ther- 

 mometer, were in geometrical progression, when the times are in an arithme- 

 tical progression, the several degrees of heat were discovered; the iron was laid 

 not in a calm air, but in a wind that blew uniformly upon it, that the air heated 

 by the iron might be always carried off by the wind, and the cold air succeed it 

 alternately ; for thus equal parts of air were heated in equal times, and received 

 a degree of heat proportional to the heat of the iron ; the several degrees of 

 heat thus found had the same ratio among themselves with those found by the 

 thermometer : and therefore the rarefactions of the oil were properly assumed 

 proportional to its degrees of heat.* 



Account of Books, viz. — /. Projluvia P^entris: or, the Nature and Causes of 

 Loosenesses plainly discovered, their Syvipt07ns, and Sorts evidently settled, the 

 Maxims for Curing them fully demonstrated, and all illustrated ivith the most 

 remarkable Methods and Medicines of all Ages ; and with some practical Obser- 

 vations concluding every Sort. By IVilliam Cockburn, M.D. F.R.S. &c. 

 London, 1701, Svo. N° 270, p. 829. 



* A mtthod if not more accurate, at least more expeditious than the above, of measuring high 

 degrees of heat, was invented some years ago by the late Mr. Wedgewood j founded on the property 

 •which argillaceous earth possesses, of contracting its dimensions when placed in the fire. See Phil. 

 Trans. Vols. 72, 74, and 76- 



