500 Zoological Proceedings of Societies. 



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 nume- 

 rous offspring, 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 monoicous 

 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. 



JVbv. 20. — A paper was read, entitled jin Account of some Experi- 

 ments on the Torpedo : by Sir Humphry Davy, Bart., F.R.S., &c. 



The authour, after noticing the peculiarities discovered by Walsh in 

 the electricity of the Torpedo, and the opinion of Cavendish that it re- 

 sembles the action of the electrical battery weakly charged, adverts to 

 the conjecture of Volta, who considered it as similar to that of the gal- 

 vanic pile. Being on the coast of the Mediterranean in 1814 and 1815, 

 the authour, desirous of ascertaining the justness of Volta's comparison, 

 passed the shocks given by living Torpedos through the interrupted cir- 

 cuit made by silver wire through water, but could not perceive the slight- 

 est decomposition of that fluid ; the same shocks, made to pass through 

 a fine silver wire, less than one-thousandth of an inch in diameter, did 

 not produce ignition. Volta, to whom the authour communicated the 

 results of these experiments, considers the condition of the organs of 

 the Torpedo to be best represented by a pile of which the fluid substance 

 was a very imperfect conductor, such as honey, and which, though it 

 communicated weak shocks, yet did not decompose water. 



The authour also ascertained that the electrical shocks of the Torpedo, 

 even when powerful, produced no sensible effect on an extremely deli- 



