306 Prof. Amici on a Property of Light, (Sec. 



gins often assigned to rivers by the natives of India, that led 

 European geographers to infer the existence of a connection 

 between the Burrampooter and Sanpoo of Tibet, as well as of 

 an anastomosis between the Burrampooter and the Ava river. 



How far all these opinions will stand the test of further ac-' 

 tual survey and local investigation, is yet to be determined ; 

 and I cannot reasonably expect a confirmation of the whole ; 

 but enough has already been favourably decided to have 

 proved very gratifying to me, and to have fully repaid me 

 for any little time and trouble devoted to so interesting an in- 

 quiry. 



I need scarcely add, that I was mainly assisted in my in- 

 quiries, while in India, by my worthy and intelligent friend, 

 Mr D. Scott, who has furnished so many interesting and va- 

 luable morceaux of research from the N.E. frontier of Bengal. 



Should you wish for any further details, I shall have g^eat 

 pleasure in furnishing you with them as far as in my power. 

 In the meantime, I trust that the readiness with which I 

 make the present communication will be accepted as an ear- 

 nest of the willingness with which I shall attend to your fu- 

 ture wishes ; being, my Dear Sir, 



Yours very sincerely, 



R. Lachlan. 



Edinburgh Castle. Feb. 20, 1826. 



Art. XXIV. — On a Property of Light, exhibited in the Ex- 

 amination of small Luminous Points by Telescopes. * By 

 Professor Amici of Modena. 



The property of light, which I propose now to explain, and 

 which I observed some time ago, enables us to distinguish the 

 discs of the satellites of Jupiter, which have a sensible diame- 

 ter from those of the fixed stars, whose diameter is inappre- 

 ciable by our eyes. 



In observing the stars with my telescopes, to which I have 



* This notice is an abstract of part of Professor Aroici's Memoir on the 

 Observation of Jupiter's Satellites in the Day~time. 



