176 PHILOSOPHICAL TRANSACTIONS. ' [anNO 1757. 



LIV, Remarks on the Heat of the Air in Julij 1757 ^ in an Extract of a Let- 

 ter from John Huxham, M.D., F.R.S. to fVilliam fVaison, M.D., F. R.S. 

 dated at Plymouth IQlh of that Month. With additional Remarks by Dr, 

 Watson, p. 428. 



* From the beginning of June last we have had a very dry season, generally 



* very warm, and sometimes excessively hot. From the 7th to the 14th of this 

 ' month the heat was violent ; greater indeed than has been known here in the 

 ' memor)' of man. I have talked with several persons, who have lived a consi- 

 ' derable time in Jamaica, Gibraltar, and Minorca ; and they severally assert, 



* that they never felt such intense heat in any of these places. On the 1 1 th, 



* 1 2th, and 1 3th of this month, Fahrenheit's thermometer, in the shade, about 

 ' 3 o'clock in the afternoon, was at 87 ; nay, on the 12th it was even above 88. 



* Abundance of people have suffered very severely from these excessive heats: 



* putrid, bilious, petechial, nervous fevers, are exceedingly common every where. 



* Dysenteries, haemorrhages, most profuse sweats, affect not only those in fevers, 



* but a vast many others. The days and nights were so intolerably hot, that lit- 



* tie or no sleep was to be gotten. The wind we had, like, the Campsin, 



* actually blew hot, though strong.* 



* On the 15th, about 7 at night, about Falmouth, Penrj'n, Truro, &c. a 



* pretty smart shock of an earthquake was felt, attended with a hollow rumb- 



* ling noise, throwing down pewter, china-ware, and such like. The tinners 



* felt it 80 fathom under ground. No great damage however was done. The 



* day before we had, about 1 1 o'clock before noon, a most violent hurricane, 

 ' which lasted 5 or 6 minutes, attended with a heavy shower.' 



Thus far Dr. Huxham. The following by Dr. Watson: 

 The heat of the air at London, during ' 



the period above-mentioned, was much greater ^7^7, July 



than has been usually observed in these high 

 latitudes; though it was never quite so severe 

 here as at Plymouth. The annexed table exhi- 

 bits the degrees of the heat, taken here upon 

 the respective days, about 4 o'clock in the 

 afternoon, by a Fahrenheit's thermometer. The 

 instrument was placed in the shade; and the 

 accuracy of the observer, who favoured me with 

 his minutes, is not to be questioned. From hence it appears, that the air at 

 London was, on several days hotter than it had been observed at Madeira for 

 10 years together: for, by Dr. Thomas Heberden's observations, mentioned in 

 the Philosophical Transactions, the heat of the air at Madeira, during that pe- 

 riod, was never but once at 80. 



