Intelligence and Miscellaneous Articles. 327 



A general accordance is observed sufficient to show the identity 

 of chemical composition in the minerals examined ; the small quan- 

 tity of potassa present in my specimen probably modified the blow- 

 pipe character a little, as I found it not to exfoliate completely, 

 and it fused without any difficulty, and even with some ebullition. 



Some of the numerous cavities in the apophyllite were empty, 

 some entirely filled with gyrolite, and in others separate plates of 

 this mineral were standing edgewise, leaving vacant spaces, while 

 upon and by the side of the plates were in some cases rhombohedral 

 crystals which proved to consist of calcite, and were sometimes pre- 

 sent alone in the cavities, which varied from being quite shallow to 

 half an inch in depth. It is mentioned by Anderson that gyrolite 

 occurs associated with stilbite, Laumonite, and other zeolites, and is 

 sometimes found coating crystals of apophyllite. 



The difference in chemical composition between apophyllite and 

 gyrolite is very well seen on comparing the respective theoretical 

 per-centages of their constituents, thus : — 



Si(X CaO. KO. HO. 

 Apophyllite . =52-70 26'00 4-40 1 6- 70 4- HF variable. 

 Gyrolite ■ ■ =52-18 32-26 15-50 



and the existence of the calcite in the cavities seems clearly to show 

 that the gyrolite is formed from the apophyllite by the waters which 

 deposited the carbonate of lime reacting on the silicate of potash, 

 and dissolving out at the same time the fluorine as fluoride of cal- 

 cium* : trial was made for fluorine on two fragments of the gyrolite, 

 but no evidence of its existence obtained. — Silliman's American 

 Journal, July 1861. 



PRODUCTION OP THE GREEN MATTER OF LEAVES UNDER THE 

 INFLUENCE OF THE ELECTRIC LIGHT. BY M. HERVE MANGON. 



It appeared interesting to ascertain whether the green matter de- 

 veloped so readily in young leaves exposed to the sun, was also pro- 

 duced under the influence of the bright light of the electric lamp. 

 This experiment has been tried by the kind aid of M. Allard, chief 

 engineer of lighthouses, who has allowed me to use for several days 

 the powerful apparatus under his control. 



The electricity was produced by a powerful electro-magnetic ma- 

 chine driven by a steam-engine. The light was that of a charcoal 

 lamp. 



The lamp was lit for eleven hours on the 30th of July, twelve 

 hours on July 31, Aug. 1, and Aug. 2, and eleven hours and a half 

 on Aug. 3. The temperature of the air varied from 22° to 25° C, 

 and that of the earth from 19° to 21° C. 



On the 30th of July, at 8 in the morning, small flower-pots, each 

 containing four grains of rye, sown respectively on the 24th, 26th, 

 27th, and 28th of July, were placed in a perfectly dark room, about a 

 yard from the lamp, and about 2 feet below the luminous focus, and 

 without the interposition of any glass. 



The grains sown on the 24th and 26th had sprouted ; the stalks 



* See Daua's Mineralogy, vol. i. pp. 232, 233. 



