346 



on the power of the telescope, and thence computes the correspond- 

 ing change in the refractive index of the fluid. The result is the 

 amount of adjustment already stated. The correction for angular 

 measurements was the 60th part of a second in every minute, for 

 every degree of thermometric change ; a quantity, Mr. Barlow ob- 

 serves, which is too small to deserve notice, except in cases of ex- 

 treme delicacy. The dispersions at 31 and at 84 are in the ratio of 

 3067 to 3084. The change in the refractive index between 32 and 

 212, supposing it to increase uniformly, would be about one tenth 

 of the whole, a proportion which is very nearly the same as the 

 actual expansion of the fluid. Hence it is considered as probable, 

 that in this and all other expansible fluids, the index of refraction 

 varies directly as the density. On the other hand it would appear, 

 that the dispersive ratio remains, at all temperatures, constantly the 

 same. 



On some Circumstances relating to the Economy of Bees. By Thomas 

 Andrew Knight, Esq. F.R.S. President of the Horticultural So- 

 ciety. Read May 22, 1828. [Phil. Trans. 1828, p. 319.] 



The author had already stated, in a former communication to the 

 Royal Society, his having noticed that for several days previous to 

 the settling of a swarm of bees in the cavity of a hollow tree adapted 

 to their reception, a considerable number of these insects were in- 

 cessantly employed in examining the state of the tree, and particu- 

 larly of every dead knot above the cavity which appeared likely to 

 admit water. He has since had an opportunity of observing that the 

 bees who performed this task of inspection, instead of being the 

 same individuals as he had formerly supposed, were in fact a con- 

 tinual succession of different bees ; the whole number in the course 

 of three days being such as to warrant the inference that not a single 

 labouring bee ever emigrates in a swarm without having seen its 

 proposed future habitation. He finds that the same applies not only 

 to the place of permanent settlement, but also to that where the 

 bees rest temporarily, soon after swarming, in order to collect their 

 numbers. 



The swarms, which were the subjects of Mr. Knight's experiments, 

 showed a remarkable disposition to unite under the same queen. On 

 one occasion a swarm, which had arisen from one of his hives, 

 settled upon a bush at a distance of about twenty-five yards ; but in- 

 stead of collecting together into a compact mass, as they usually do, 

 they remained thinly dispersed for nearly half an hour ; after which, 

 as if tired of waiting, they singly, one after the other, and not in 

 obedience to any signal, arose and returned home. The next morn- 

 ing a swarm issued from a neighbouring hive, and proceeded to the 

 same bush upon which the other bees had settled on the preceding 

 day ; collecting themselves into a mass, as they usually do when 

 their queen is present. In a few minutes afterwards a very large 

 assemblage of bees rushed from the hive from which the former 



