290 Linnean Society. [March 17, 



and a half of fluid. The temperature of the external atmosphere, 

 when the hive was examined at seven o'clock in the morning, was 

 59° F., and that of the hive, at some distance within the entrance, 

 69° F. 



On another occasion, a few days afterwards, at about the same 

 time in the morning, when the temperature of the atmosphere was 

 61° F., that of the vapour within the phial as it issued from the hive, 

 but at nearly four inches' distance from it, was 71°'5 F., while the 

 interior of the upper part of the hive, as ascertained by a thermo- 

 meter inserted through the top and undisturbed for several days, 

 was only 69° F, The bees were then quiet at the top of the hive, 

 but were in activity at the lower part. The temperature of the hive 

 and the quantity of fluid thus seemed to depend on the amount of 

 respiration consequent on the greater or less activity of the bees, as 

 the author has shown respecting temperature in the ' Philosophical 

 Transactions' for 1837. 



On another occasion, when the bees were quiet and the tempe- 

 rature of the external atmosphere was only 41° F., that of the top of 

 the hive was 54° F., but that of the vapour from the entrance-hole 

 was 59° F. The quantity of fluid then condensed in the phial, du- 

 ring a night of twelve hours, was scarcely three minims. 



These experiments seemed to show that the vapour is in the 

 greatest quantity when the bees are most active, and in the least 

 quantity when they are inactive ; and the author believes that it is 

 the carbonic acid, the result of respiration, and held in solution in 

 this vapour, which occasions the darkened colour of the combs. 



March 17. 



The Lord Bishop of Norwich, President, in the Chair. 

 Mr. Samuel Osborn was elected a Fellow. 



Read a paper " On the Siliceous Armour of Equisetum hyemale, L., 

 with an account of its hitherto undescribed Stomatic Apparatus." 

 By Golding Bird, Esq., A.M., M.D., F.R.S., F.L.S. &c. 



Dr. Bird commences his paper by referring to the observations of 

 Mr. Sivright on the large amount of silica contained in Equisetum 

 hyemale, and those of Dr. Brewster on the general arrangement of 



