308 Observations on the Temperature of the 



great influence on the temperature of the water, from their 

 absorbing the solar rays, and also from many of them being 

 taken from the sand-banks, which, for two or three hours 

 before, have been dry, and exposed to astral or solar radia- 

 tion, will, I believe, be readily granted. 



All the trials of temperature were made by drawing a 

 phial of water, rejecting the two first fillings ; then quickly 

 testing the third with a small bulbed thermometer. This 

 method was fully relied on, after it had been repeatedly com- 

 pared and found to agree with the result obtained, by the 

 direct insertion of the instrument into the surface of the 

 water, with the indication read off while immersed. 



The observations were made at 9 A.M. weekly^ commencing 

 in November 1844, excepting during weather where I wanted 

 to ascertain the rate of change, when the temperatures were 

 taken daily, or in some instances oftener. 



From the middle of November 1844 to the end of Decem- 

 ber, there was a period of calm or foggy weather, with severe 

 frost in December. 



The temperature of the Mersey water, when the tide- 

 current throws up ground water, on 13th December, was 

 35° r. From this point up to 42° the thermometer ranged, 

 during January and February, only reaching 35°, when the 

 air had been, for several days, calm as well as frosty. 



o 



1845, March 19. Temperature of sea- water, . . . 35*3 



21 36 



24 39 



26 40 



2^ 40-7 



28 43 



On the evening of the 21st March the weather underwent 

 a complete change. The long continental-like winter of 

 1844-5 may be said to have broken up on that day ; for the 

 change from a severe frost was immediately succeeded by 

 warm westerly winds, with rain ; and as the large mass of 

 sea- water filling the estuary of the Mersey had been then all 

 cooled down to 36° F., I thought the opportunity a favourable 

 one for trying the rate of change. From the above observa- 

 tions it will be noticed, that the rate for seven days was 

 exactly l°per diem. After the 28th, the temperature of the 

 water was stationary till the 3d April. The rapidity of this 



