332 Intelligence and Miscellaneous Articles. 



result of any change produced upon the surface by external causes. 

 It is exhibited, under the usual modifications, if the surface of the 

 chrysammate is in optical contact with fluids and with glass ; and 

 when the crystal is in the act of being dissolved, or when a fresh 

 surface is exposed by mechanical means, the superficial action of 

 the crystal upon light is in both cases the same. When the chry- 

 sammate is re-crystallized from an aqueous solution, it appears in 

 tufts of prisms of a bright red colour, the golden reflexion being 

 overpowered by the transmitted light ; but when these tufts are 

 spread into a film by pressure, the golden yellow colour re-appears. 

 When the crystals of chrysammate are heated with a spirit-lamp, 

 or above a gas-burner, they explode with a flame and smoke like 

 gunpowder ; and, by continuing the heat, the residue melts and a 

 crop of colourless amorphous crystals is left. I have found the 

 same explosive property in the aloetinate of potash. — Athenceum. 



INFUENCE OF NITROUS OXIDE GAS ON VEGETATION. 

 BY M. VOGEL, JUN. 



It is generally admitted that nitrous oxide gas is incapable of sup- 

 porting life, although a candle which has been blown out is relighted 

 by immersion in this gas, and burns with greater brilliancy in it than 

 in atmospheric air. The rapid combustion of the candle is owing to 

 the ready decomposition of this gas at a high temperature,— ? a de- 

 composition which cannot be effected in the lungs by respiration ; 

 whereas the air, which is a mere mixture of oxygen and azotic gases, 

 readily yields its oxygen in the act of respiration. 



The author obtained the nitrous oxide, used in his experiments, 

 from pure nitrate of ammonia ; and into a vessel containing this gas 

 he introduced seeds of cress spread on a moist sponge. The intro- 

 duction of the seed w r as effected under water, and so as to prevent 

 the access of atmospheric air, and it was expelled from the sponge 

 by slight pressure ; sufficient water was left in the bottle for germi- 

 nation ; and after the sponge and seeds had been introduced, it was 

 hermetically closed. 



In order to make a comparative experiment, a sponge with cress 

 seed was also placed in a bottle containing atmospheric air. After 

 some days the seed in this bottle began to germinate and to form 

 leaves ; but the reverse was the case in the bottle containing the 

 seed in nitrous oxide. Not the slightest appearance of germination 

 was perceptible : the seeds, nevertheless, were swelled and covered 

 with mucus, but without any change which indicated germination. 

 After two weeks had elapsed, the seed and sponge were removed from 

 the nitrous oxide, and as soon as they came into the air they began 

 to germinate ; from this it follows that the seed had not lost its 

 power of germinating by exposure to nitrous oxide ; whereas seeds 

 cease to germinate after they have been in contact for a short time 

 with several other gases. 



The nitrous oxide gas in which the seed had remained for two 

 weeks, underwent no alteration ; it did not contain even a trace of 

 carbonic acid, and re-lighted a candle. 



