474 [Assembly 



POTATO ONIONS. 



On the culture of onions in Russia, from the imperial Economi- 

 cal Society of St Petersburgh, by Mons. Sailtet. 



The weekly Journal of Mussehl, reports the method of cultivating 

 onions adopted in Russia, which consists in cutting the onion into 

 four parts, leaving the quarters united at the root, and the onion 

 having been first hung up and dried in smoke. For want of fresh onions, 

 the smoke dried, still full of sap were quartered down to the roots, 

 and being planted, each produced four fine onions, each of which had 

 its seed stalk. It seems this mode is unknown out of Russia. The 

 onion thus treated is not that from seed, it is the potato-onion. 



Baron Foelkersahm, a member of the society, thinks it his duty 

 to state, that he has on his estate, followed this method for thirty 

 years, and has constantly had abundant crops. 



LIGHT AND VEGETATION. 



Effects of Light and Shade upon Vegetation, by A. Poiteau. 



Vegetables are invested with their colors by chemical combinations 

 favored by light and warmth. Red is produced by the direct rays 

 of the sun on fruit — leaves are tinged when they begin to decay. 

 The green color of leaves and bark is caused by light. Carbonic 

 acid is the principal nourishment of plants. It is composed of oxygen 

 and carbon — it exists in a gaseous condition in water, earth and 

 atmospheric air; vegetables are very fond of it, they inspire it, with 

 water through their roots, through the pores of tender bark, and 

 throuo-h their leaves, with the humidity of the air. But as they can 

 be nourished only by carbon, they are obliged to decompose the car- 

 bonic acid in order to acquire the carbon and to reject the oxygen. 

 Those plants which have the deepest green color, decompose the car- 

 bonic acids best. 



It is by means of light that they thus decompose the carbonic 

 acid — for when plants are placed in obscurity, they only disengage 

 it, but do not decompose it, thus rendering the air about them un- 

 healthy for man. It is believed the violet ray decomposes it less than 

 the white light. 



