Miss Zornlin on the Periodical Shooting Stars. 347 



proaching the influence of animals who introduce this acid 

 into the air, and that of vegetables, which deprive it of it ? 



No ; this phenomenon, you are aware, is a simple meteor- 

 ological phenomenon. It is with carbonic acid as with aque- 

 ous vapour, which forms on the surface of the sea, to become 

 condensed elsewhere, fall again in rain, and be reproduced 

 under the form of vapour. 



This water, which is condensed and falls, dissolves, and 

 carries with it carbonic acid; this water, which evaporates, 

 yielcfs up this same gas to the air. 



A great meteorological interest would attach to the observa- 

 tion of the variations of the hygrometer, and those of the sea- 

 sons, or of the state of the sky with the variations of the car- 

 bonic acid of the air; but hitherto all tends to show that these 

 rapid variations constitute a simple meteorological event, and 

 not, as had been thought, a physiological event, which, singly 

 considered, would infallibly produce variations infinitely slower 

 than those which are, in fact, observed as much in towns as 

 in the country itself. 



Thus the air is an immense reservoir, whence plants may for 

 a long time derive all the carbonic acid necessary for their 

 wants ; where animals, during a much longer time still, will 

 find all the oxygen that they can consume. 



It is also from the atmosphere that plants derive their azote, 

 whether directly or indirectly : it is thei*e that animals finally 

 restore it. 



The atmosphere is therefore a mixture which unceasingly 

 receives and supplies oxygen, azote or carbonic acid, by 

 means of a thousand exchanges of which it is now easy to 

 form a just idea, and the details of which a rapid analysis will 

 now enable us to appreciate. 



[To be concluded in our next Number.] 



XLIX. On the Periodical Shooting Stars, and on Shooting 

 Stars in general. By Miss Zornlin*. 



F the meteorological nature of the periodical shooting 

 stars of August and November, little doubt, I should 



O 



think, can remain in the mind of any one who has observed 

 and considered the general character of the attendant phe- 

 nomena. It may, however, be desirable to adduce a few 

 instances in support of this assumption. 



In our own island, the November periodical shooting stars 



* Communicated by the Author. 



