74 Royal Society. 



very fluctuating nature ; the action arising from them being either 

 positive or negative, and its sign also changing in each revolution 

 as the masses are turned round a vertical axis ; and he observes that 

 such action may either fall short of that arising from gravitation or 

 exceed it many times. Such disturbing force he conceives can be no 

 other than a magnetic influence ; not however one of the ordinary 

 kind, but that which Faraday has recently discovered as affecting 

 all diamagnetic bodies. 



The author concludes by proposing methods by which the inquiry 

 should in future be conducted, so as to obviate or eliminate this 

 source of error. Such an inquiry, he remarks, would, by exhibit- 

 ing the magnetic and diamagnetic powers under new aspects, lead, 

 in all probability, to important consequences. 



March 18.—" Researches to determine the Number of Species 

 and the Mode of Development of the British Triton." By J. Hig- 

 ginbottom, Esq., F.R.C.S. Communicated by Thomas Bell, Esq., 

 F.R.S. 



The observations of the author, of which he gives a detailed ac- 

 count in the present memoir, have led him to the following con- 

 clusions : — 



Two species only of the genus Triton are met with in England ; 

 namely, the Triton verrucosus and the Lisso-triton punctatus. It is 

 three years before the animal is capable of propagating its species, 

 and four years before it attains its full growth. In its tadpole state, 

 it remains in the water till its legs acquire suflficient strength to 

 qualify it for progressive motion on land. While a land animal, it 

 is in an active state during the summer, and passes the winter in a 

 state of hybernation ; but does not then, as has been erroneously 

 supposed, remain at the bottom of pools. Very dry, or very wet 

 situations are incompatible with the preservation of life during the 

 period of hybernation. At the expiration of the third year, the 

 triton revisits the water, in the spring season, for the purposes of 

 reproduction, and again leaves it at the commencement of autumn. 

 Impregnation is accomplished through the medium of water, and 

 not by actual contact. The growth and development of the triton 

 are materially influenced by temperature, and but little by the action 

 of light. The triton possesses the power of reproducing its lost 

 limbs, provided the temperature be within the limits of 58° and 75° 

 Fahrenheit ; but at lower temperatures, and during the winter, it 

 has no such power. 



April 15. — " On the Proper Motion of the Solar System." By 

 Thomas Galloway, Esq., A.M., F.R.S. 



The object of this paper is to communicate the results of a calcu- 

 lation for determining the direction of the proper motion of the 

 solar system from the apparent proper motions of stars in the 

 southern hemisphere, deduced mostly from a comparison of the 

 observations made by Lacaille at the Cape, about the middle of the 

 last century, with the recent observations of Mr. Johnson and the 

 late Professor Henderson at St. Helena and the Cape respectively. 

 After adverting to the papers of Sir William Herschel in the Philo- 



