Correction of Miasmata iii a Comervatory. 



65 



the open garden, remarkably well, and seem to be equally 

 hardy with tlieir congeners. I subjoin a sketch {fg. 14.) and 

 description of this curious esculent, as supplied me in a com- 

 munication from this friend. 



" The above is somewhat the appearance of a plot of a 

 variety of cow cabbage that I saw growing in Jersey. It is 

 much cultivated there, and attains the height of from 4 ft. to 

 loft, or 12ft. The little farmers feed their cows with the 

 leaves, plucking them from the stem as they grow, and leaving 

 a bunch or head at the top. The stems are very strong, and 

 used for roofing small out-buildings ; and after this purpose is 

 answered, and they are become dry, they are used for fuel. 

 When the gathering of the leaves is finished at the end of the 

 year, the terminating bud or head is boiled, and said to be 

 particularly sweet." — Jo/m Murrai/. 



Correction of Miasmata arising from the decaying Vegetation 

 in a Conservatory^ S^'c. — The chloride of lime in solution 

 would certainly correct various gases and vapours arising 

 from this cause. The Hon. Henry Cavendish, by transmitting 

 a successive series of electric sparks through a confined quan- 

 tity of atmospheric air, soon obtained evident traces of the 

 production of nitrous acid gas, in the red vapour which arose. 

 The chemical constitution of atmospheric air is 21 oxygen, and 

 79 azote, or nitrogen, independent of the minute proportional 

 of carbonic acid gas, which has been variously estimated. Now, 

 a reversal of these proportionals would form nitrous acid ; and 

 there can be no doubt whatever, that a quantity of nitrous acid 

 gas is formed in every thunder-storm, one of the most power- 

 ful disinfecting agents in existence ; that, in truth, employed 



Vol. V. — No. 18. f 



