3T0 Royal Society of London, 



But these last eclipses were observed with a telescope of 

 Caroch^, which, though u very good one, magnifies only 58 

 times, not being able to carry along with me, to Rio-Negro, 

 the large telescope by Dollond. 



Declination of the magnetic needle at Cumana on the 27th 

 of October 4^ 13' 45"; at Caraccas, 4^*38' 45"; at Calabozo, 

 4^ 54' of the old division. 



The port of La Guayra is exactly 29' in time west from 

 Caraccas ; and I hope that, by giving immersions and emer- 

 sions, the meridian of Caraccas will be properly fixed. 



I have described, with Bonpland, more than 1200 plants** 



XLVI. Proceedings of Learned Societies. 



ROYAL SOCIETY OF LONDON. 



April so. The reading of Dr. Herschel's observations 

 on the nature of the sun was concluded. The doctor re- 

 marks that, if the luminous matter of the sun was a fluid, or 

 even of a nature similar to an atmosphere, every opening 

 must, by the laws of hydrostatics, be instantly filled up. His 

 supposition is^ that the sun is surrounded by an atmosphere of 

 considerable density on which the luminous matter floats, 

 and which he conjectures to be of similar nature to our 

 clouds. Having consulted all the astronomical acounts of 

 observations on the telescopic appearance of the sun, and com- 

 j)ared them with the registers of the price of corn for those 

 years in which they were made ; he infers, from a careful ex- 

 amination of the whole, that in those years in which few 

 openings were seen, there has been a rise in the price of 

 wheat in consequence of a scarcity, arising from a smaller 

 emission of the matter of heat. 



* A Letter from Haspel-la-Chenaye, chemist at Guadaloupe, dated 

 Jan. 5, states, that M. Humboldt had set out for the Havamiah, after 

 having left with the agent of the government at Guadaloupe a box for 

 the Institute and two packets, one for Fourcroy and the other for Delam- 

 bre. As the box has not yet arrived, nor the packets addressed to Four- 

 croy, it is to be presumed that the above letter is not that mentioned 

 by Haspel-la-Chenaye. 



On 



