108 Correspondence of J. Nickles. 
which candles could be made. A hectar of Sorgho gives more than 100 
kilograms of this substance. 
The trials made to acclimatize the trees of Gutta Percha have not yet 
been successful. The same is true of the trees of quinina. 
Artesian Wells in Paris—The construction of Artesian wells in the 
Bois de Boulogne, spoken of in a previous number, is progressing with ac- 
tivity. The boring is now carmed down 435 metres, and it is hoped 
to reach by the end of October a depth from which the water will rise. 
No difference has yet been experienced in the nature and thickness of 
e earth pierced by the auger and that which it was necessary to pierce 
for the establishment of the Artesian well of Grenelle. It is known that 
the section of the wells at Passy will be 60 centimeters in diameter 
throughout its depth, and that it will be sunk at least 25 metres in the 
humid bed of greensand that lies at an average of 550 metres below the 
plain of Passy. 
boring is much easier at Passy than at Grenelle. The consiruc- 
tion of the latter well continued through seven years ; and it was several 
times abandoned because of discouragement. Arago and Héricart de 
resuming 
en @ same direction; Hind and Cooper were soon to distance 
the French astronomers. However Chacornac, who meanwhile had been 
attached to the Observatory of Paris, continued his charts. They have 
Just been published at the expense of that observatory. They will be 
more complete than the former, and quadruple the dimensions of those of 
estial d 
egree. 
ese charts contain all the stars of the 12th magnitude and many of 
the 13th magnitude: they extend above and below the ecliptic to 5° of 
