VOL. XXVII.] PHILOSOPHICAL TRANSACTIONS. QQq 



prised to find, that there was very little brains in it, certainly not so much as in 

 a rabbit, the whole cavity not large enough to hold an ordinary walnut. 



Experiments on Fishes kept in PTateVf under different Circumstances. By Mr. 

 Fr. Hauksbee, F.R.S, N° 333, p. 431. 



The fishes used in the following experiments were gudgeons: which are natu- 

 rally very brisk and lively in the water, and can live a considerable time out of 

 it. I put three into a glass vessel with about 3 pints of common water; these 

 fishes were to be a standard to compare the others by. Into another glass I 

 put three more to a like quantity of water, which just filled it; I then screwed 

 down a brass plate with a leather between, to prevent a communication with 

 the water in the glass and the external air, and that it might the better resemble 

 a pond of water frozen over, on which account this experiment was made. I 

 suff^ered as little air as possible to remain on the surface of the included water. 

 The third glass had a like quantity of water, which first by boiling, then by 

 continuing it a whole night in vacuo on the air pump, was completely purged of 

 its air. Into this water also I put the same number of gudgeons aaiuito the 

 former; and then waited the event. It was about half past 10 o'clocHjj^ the 

 morning when I began the experiments, and in about half an hour from that 

 time, the fishes in the exhausted water, or water purged of its air, began to 

 discover some uneasiness by a more than ordinary motion in their mouths and 

 gills, or respiration, if I may call it so, differing from the fishes in the other 

 glasses, which at the same time showed no alteration : only I observed that they 

 would now and then ascend to the top of the water, but suddenly swim down 

 again: and in this state they continued for some considerable time, without any 

 sensible alteration. About 5 hours after the last observation, the fishes in the 

 exhausted water became not so active, on a motion given to the glass that con- 

 tained them, as before: and the gudgeons included without any communication 

 with the outward air, now began considerably to abate of their vivacity. At 7 

 in the evening, the included fishes lay all at the bottom of the glass, with their 

 bellies upwards: nor on shaking the glass could I put them in motion, or cause 

 them to stir their fins or tail, only I could observe a motion in their mouths, 

 which showed they were not quite dead. In this state they lay for some time; 

 but considering the experiment would not be complete, if I did not attempt 

 their recovery by taking off the brass cover, being very certain they must have 

 died in some small time under the circumstances they were in, I took off the 

 cover, and gave the surface of the water a free and open communication with 

 the external air. At about 10 at night I observed them again; when their re- 



