274 Gironides of Science. [April, 



the ' Photographic Journal' It was observed, we heheve, indepen- 

 dently by M. Bertbelot and Mr. E. Chamb(>rs Nicholson, that an 

 acid which, although of a high degree of purity, is not glacial, 

 becomes inflammable when the temperature is raised to the boihng- 

 point. If we take, for instance, about a drachm of the acid of 95 

 per cent., and heat it in a test-tube to the boiling-point, it will be 

 found that the vapour takes fire on applying a lighted match, and 

 burns steadily as long as the ebulHtion is maintained ; if, however, 

 10 per cent, of water be mixed with the sample, there will be 

 great difficulty in causing inflammation, a,nd the vapour, when 

 ignited, will only burn with a lambent flame of pale- blue se[iarated 

 cones, whilst below this strength the acid vapour is altogether un- 

 inflammable. By this test then (avoiding a too prolonged ebulli- 

 tion, which increases the strength of a weak acid), we have a ready 

 means of estimating the quahty of liquid samples of a high degree 

 of concentration, without resorting to the more tedious method of 

 acidimctry. It has only to be stated, in conclusion, that the boil- 

 ing-point of the ordinary qualities of acetic acid, although higher, 

 is so httle removed from that of water, that the indications of the 

 thermometer are not much more to be relied upon than those of the 

 hydrometer. In many respects carbolic acid imitates the deport- 

 ment of acetic acid in the characters above described ; it hkewise 

 becomes glacial upon separation of the last traces of water. 



M, Chabrier has studied at nitrification works, in particular 

 circumstances, the difierent degrees of oxidation of the nitrogen, 

 and especially nitrous acid. He has devoted attention to the esti- 

 mation of this acid in saline mixtures, where nitrites and nitrates 

 occur together with reducing agents, and has submitted to the 

 Academy the result of the first part of his researches. The facts 

 contained in this memoir are deduced from the following, conclu- 

 sions: — 1st, in liquids containing at the same time nitrites, nitrates, 

 and organic matter, the nitrous acid of the nitrites may be deter- 

 mined by the decolourizing fiction which hyposulphite of soda 

 exerts on the iodide of potassium in presence of stanch, and dilute 

 sulphuric acid ; 2nd, in the absence of nitrates and organic matter, 

 the determination could be more easily made by the decolourizing 

 of indigo solution, operating with the aid of heat, bat out of contact 

 with the air, 



A combination of iodic acid with oxide of ethyl has been 

 prepared by M. K. Lisensko. He finds that a mixture of equal 

 volumes of ethyl iodide, and dry ether, readily acts upon argentic 

 iodate. If the temperature is not allowed to rise above 10^ C, 

 the liquid remains colourless, and the new ether undecomposed. 

 The solution distils between 37" and 40 ^ The distillate at first 

 floats upon the water with wliicli it had been mixed, but on 

 passing a current of air through the liquid, in order to drive oft' 



