270 Correspondence of J. Nicklés. 
tanvert, (Savoy), at 2000 metres above the level of the sea; and he has 
proposed to take the air from a much greater elevation by the aid of a 
bal 
the conditions, it will doubtless be possible to obtain others, as Paul Lau- 
rent has already done with the infusoria in a work of which we shall 
&c., but it has heretofore lacked the indispensable element, ph e 
acid, w never been detected in ra is chasm in the 
? . 
series of fertilizing principles of meteoric waters, has at length been filled 
by Barral, wh 
hectare (or 24 English acres). Now since the researches of Boussingault 
have proved that a hectolitre, (2% bushels), of wheat takes from the sol 
about one kilogram of phosphoric acid, we see that to obtain seven a 
