Intelligence and Miscclla?ieous Articles. 73 



If this salt be exposed to atmospheric air, it is altered by the ab- 

 sorption of carbonic acid, but it does not deliquesce. Placed under 

 a receiver over sulphuric acid, it expands, first at the surface, and 

 after some time even to the centre of the crystal, but it presences 

 its form. When heated to 122° Fahr. it fuses and forms a sirupy 

 liquid, which on cooling does not solidify, but long retains its liquid 

 state. 



The form of these crystals has been ascertained by M. Norden- 

 skiold ; they belong to the prismatic system. 



M. Fritzche has succeeded in obtaining another hj'drate of the 

 above silicate of soda, but he has not been able to ascertain the cir- 

 cumstances requisite for its production ; it was procured in preparing 

 the foregoing in large quantity ; in spherical masses, the surfaces of 

 which were covered with crystals ; the crystals, though of determi- 

 nate form, could not be measured, but belonged to the system of 

 axinite ; the properties of the salt were not determined with preci- 

 sion, owing to the small quantity obtained ; this consisted of 

 By analysis. Theory. 



Silica 26-20 26-94 



Soda 26-80 26-53 



Water 47-00 46-53 



100- 100- 



The symbol is Na3 Si^-j- 18 B^—L'Institut, No. 254. 



[Representing silica by 16, soda by 32, and water by 9 ; the first 

 salt may be regarded as a disilicate of soda with 10 eqs. of v/ater; 

 and the second as containing 6 eqs. of water. — R. P.] 



RESPIRATION OF PLANTS. 



M. Colin has read before the Academy of Sciences, a memoir on 

 the respiration of plants, the experiments detailed in which were 

 performed with M. Edwards, Sen. 



Scarcely any of the pha?nomena of the respiration of plants have 

 been hitherto recognised, except the disengagement of carbonic acid 

 gas ; and this has been explained by the combination of the oxygen 

 of the air with the carl)on of the grain. Thus, according to this 

 theorj'', the grain is only acted upon by the atmosphere, and the 

 action of water on the respiration of plants is not considered. In 

 the respiration of leaves, carbonic acid is evolved during the night, 

 and during the day it is absorbed, and oxygen is disengaged by the 

 direct solar rays ; and these facts are explained on the supjjosition 

 that the carbonic acid absorbed is decomposed by the plant, its 

 carbon approjjriated, and the oxygen disengaged. But this explana- 

 tion suj)poses tlie plant to possess a decomposing power which to 

 MM. Edwards and Colin it seems difficult to admit ; and they have 

 in consequence resumed the examination of this function of plants. 



Hitherto the cxiieriments performed on the respiration of grain 

 have always been performed in the air ; or when they have been per- 

 formed in water, the cxpl-anationa of the phenomena have been 



