Mr. J. BlackwalPs Ornithological Notes. S77 



unusual coldness and backwardness of the season : — ' On the 

 mornings of the 5th and 6th of June 1816, the gardeners could 

 have taken up hundreds of these birds in their hands : they were 

 collected in knots, and sat on the grass in parcels of thirty and 

 forty. This, there is reason to believe, was owing both to cold 

 and hunger.-' — Suffolk Chronicle, June 15, 1816. The same 

 summer many house martins were found dead on the ground in 

 Norfolk, and others were so weak that the cats sprang upon 

 them and caught them as they flew near the ground. A pair of 

 these birds, which had completed a nest under the eaves of our 

 house, were both found dead in it before any eggs were laid. 

 From the above circumstances, birds of this kind were unusually 

 scarce throughout the summer." 



The effects produced by variations in temperature upon the 

 dormouse, Myoxus avellanarius, and other animals whose liability 

 to become torpid is unquestionable, claim attention in the next 

 place. 



Having obtained five healthy dormice, I endeavoured at va- 

 rious periods in the year 1824 to render them torpid by artificial 

 means. Two of them were placed in a tall cylindrical glass jar, 

 with a supply of flax and cotton for the construction of a dormi- 

 tory ; and when they were familiar with their new residence, it 

 was weighted to keep it steady, and put into a tub containing 

 cold water, which rose within a few inches of its top. The tem- 

 perature of the water was further reduced by causing to be 

 speedily dissolved in it finely pulverized muriate of ammonia 

 and nitrate of potash mixed in equal quantities, the degree of 

 cold produced in the glass jar being ascertained by means of a 

 small thermometer included within it. Experiments of this kind 

 were soon perceived to be too uncertain in their results to effect 

 the purpose for which they were instituted ; for though the dor- 

 mice sometimes became perfectly lethargic, yet it frequently hap- 

 pened that no such consequence followed, the rapid fluctuations 

 in the temperature of the water, and the motion unavoidably at- 

 tendant upon the process, combining to stimulate the animals 

 and prevent torpidity. 



Disappointed in this attempt, I resolved to rely on the natu- 

 ral temperature of the atmosphere solely ; and on suspending a 

 cage containing two of the dormice in the open air from a mn- 

 dow having a north aspect, whenever the thermometer was un- 

 usually low for the season, I had the satisfaction to find, that by 

 this simple expedient they were rendered completely torpid at 

 intervals in every month of the year 1824 ; the other three dor- 

 mice continuing quite alert on those occasions if subjected to the 

 influence of a high degree of temperature. After constructing a 

 comfortable bed of flax and cotton on being exposed to a cold 



Ann, ^ Mag, N. Hist, Fo/.xix. 27 



