382 History of Mechanical Inventions, and 



same remark applies not only to the permanent place of settlement, but 

 also to the place 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 show- 

 ed a remarkable disposition to unite under the same queen. On one occa- 

 sion, a swarm which had arisen from one of his hives settled upon a bush, 

 at a distance of about twenty-five yards ; but instead of collecting toge- 

 ther into a compact mass, as they usually do, they remained thinly dis- 

 persal for nearly half an hour, after which, as if tired of waiting, they 

 singly, and one after the other, and not in obedience to any signal, arose 

 and returned home. The next morning a swarm issued from a neigh- 

 bouring 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 for- 

 mer swarm had issued, and proceeded directly to the one which had just 

 settled, and instantly united with them. — The author is led from these 

 and other facts to conclude, that such unions of swarms are generally, if 

 not always, the result of previous concert and arrangement. 



He next proceeds to mention some circumstances which induce him to 

 believe that sex is not given to the eggs of birds, or to the spawn of fishes 

 or insects, at any very early period of their growth. Female ducks, kept 

 apart from any male bird till the period of laying eggs approached, when 

 a musk drake was put into company with them, produced a numerous off- 

 spring, six out of seven of which proved to be males. 



The mule-fishes found in many rivers where the common trout abounds, 

 and where a solitary salmon is present, are uniformly of the male sex : 

 hence the spawn must have been without sex at the time it was deposited 

 by the female. 



Mr Knight states that he has also met with analogous circumstances in the 

 vegetable world, respecting the sexes of the blossoms of monoecious plants. 

 When the heat is excessive, compared with the quantity of light which 

 the plant receives, only male flowers appear : but if the light be in excess, 

 female flowers alone are produced. — Proceedings of Royal Society, Phil. 

 Mag-, p. 60. 



Art. XXV.— HISTORY OF MECHANICAL INVENTIONS AND 

 OF PROCESSES AND MATERIALS USED IN THE FINE AND 

 USEFUL ARTS. 



1. Description of the Winch Bridge, the oldest Suspension Bridge in Eng- 

 land. Communicated by W. C. Trevelyan, Esq. 



Having, along with my brother, lately made a short excursion in the 

 upper part of Teesdale, where there is some very beautiful scenery, I took 

 the opportunity of examining the Winch Bridge, which is the oldest chain- 

 bridge in Britain and probably in Europe. As all the accounts of it I have 

 seen are very incorrect in regard to its dimensions, and as I think it inte- 



