032 PHILOSOPHICAL TRANSACTIONS. [aNNO 1775. 



From the 3d of May to the 4th of June inclusive, a thermometer placed within 

 a tent, under the shade of trees, was almost every day above 1 00°, and several 

 times above 109°, once at 1 12°, The trees under which the tent was placed, 

 formed a very thick shade ; so that probably these heights are more likely to fall 

 short of the true heat of the open air at that time, than to exceed it. The 

 least height he met with of the thermometer in the open air in the shade, is 

 42°; which it was at twice in the month of January, at ^ a.m. The greatest 

 heat is on June Qth, at noon, when it was at 114°, the sky cloudy ; the ther- 

 mometer within doors at the same time 95°, which is less than it had frequently 

 been in the month of May ; so that it seems likely, that the heat in the open 

 air in May had frequently been above 114°. During the voyage to England, 

 the thermometer was placed in the round-house, and was observed regularly at 

 8 in the morning, at noon, and at 3 in the afternoon ; the winds and weather 

 are also set down. The round-house is one of the uppermost row of cabins, 

 and is reckoned the coolest and most airy part of the ship. From February 13 

 to April 7j between Madras and the southern tropic, the thermometer was con- 

 stantly between 77° and 86°, and very seldom lower than 80°. From that to 

 April 23, lat. 34° 12', about 15° e. of the Cape of Good Hope, between 70° 

 and 80°. Thence to May 20, at St. Helena, between 62° and 72°. Thence to 

 August 2, in lat. 43° 14' n, between 71° and 80°; and thence to August 15, 

 in the British Channel, between 62° and 70°. At land it is well known that the 

 heat is usually considerably greater in the middle of the day, than in the morn- 

 ing or night ; but it appears from these observations, that in febe open sea, there 

 is scarcely any sensible difference ; for in settled weather, the difference between 

 the different times of the day was rarely more than 1°, oftener none at all. In 

 unsettled weather there was frequently a difference of 2°, sometimes 4°, scarcely 

 ever more ; but then there seems no connection between this difference and the 

 time of the day, it being as often colder in the middle of the day than in the 

 morning or evening, as warmer. There is added a register of the thermometer, 

 in the soldiers' barracks at Allahabad, on June 8, 1769, when from 10 in the 

 morning to 8 in the afternoon it stood constantly above 100°, in the hottest part 

 of the day at 1 07°, and during the whole night between 99° and 98°. 



Sir Robert Barker gives the following account of the general state of the 

 weather in Bengal. 



The rains at Bengal generally set in between the 1st and 15th of June, and 

 continue till the middle of October, when it remains fair till Febmary, the 

 wind blowing mostly from the n. e. quarter, in which month and March it is in- 

 terrupted by the n. w. squalls, attended with violent gusts of wind, thunder, 

 and lightning, with short, but excessive hard showers of rain or hail, commonly 

 one, but rarely 2 in each day. From the middle of March to the middle of 



