300 INFUENCE OF PROTOXIDE OF NITROGEN 
served, that a weak solution of the alkalies is to be avoid- 
ed, and that the stronger or denser they are made, the more 
perfectly will they separate the impurities from the oils and 
fats. The matter, which is precipitated in the refining of 
the above oils and fats may be used in the manufacture of 
soap; the nature of the soap depending upon the alkali made 
use of. If it is required, an inferior oil or fat may be re- 
covered from the deposit formed by neutralising the alkali 
by an acid. For this purpose the sulphuric acid, diluted 
with water, may be employed. 
The patentee states that he is aware of the alkalies, pot- 
ash and soda, having been used and recommended for the 
purification of oils and fats, but to the best of his belief they 
have never been employed for the purification of the oils 
and fats mentioned above, when those oils are refined for 
the purpose of being applied as described. He therefore 
claims the refining and purifying of olive oils, lard oil, tal- 
low, and lard, for the purposes already mentioned, by treat- 
ing them as herein described. — Newton's Journal. 
ART. LXVI.— ON THE INFLUENCE OF PROTOXIDE OF NITRO- 
GEN UPON VEGETATION. 
By M. Vogel, Jun. 
It is generally admitted that nitrous oxide is not capable 
of sustaining life, although a candle blown out is relighted, 
and burns with more brilliancy in this gas than in atmos- 
pheric air. The rapid combustion of the candle is owing 
to the easy decomposition of this gas at a high temperature 
— a decomposition which cannot be effected by the lungs 
