196 ANNUAL OP SCIENTIFIC DISCOVERY. 



one. To examine the chemical composition of the cubes transformed 

 by the action of acetic acid, they were reduced to a fine powder, and 

 well washed ; the powder was then dried. The cubes of gray cast iron, 

 which originally weighed 15.324 grammes, weighed after the two 

 years treatment only 3.489 grammes, and their specific gravity was 

 reduced from 7.858 "to 2.751. From the figures, obtained upon care- 

 ful analysis, it appears that the largest part of the nitrogen originally 

 existing in the cast iron remains in the graphitoid substance, and only 

 a small portion is transformed into ammonia. He has ascertained by 

 direct experiments that it is silicium and not silica that enters into 

 the composition of the carbonaceous mass. Like silicium, the quan- 

 tity of carbon found in the carbonaceous compound does not represent 

 the whole of the carbon preexisting in the cast iron, as carburetted 

 hydrogens are given off during the slow action of the acetic acid in 

 the iron. 



Though in the present state of his researches Dr. Calvert considers 

 it would be premature to assign any definite composition to this sub- 

 stance, the inference is that it is composed of a sesqui ferride of iron 

 with a nitride of silicium. 



DISINTEGRATED BLACK LEAD. 



A new process of preparing graphite, devised by Mr. Brodie, of 

 Oxford, Eng., is a subject of great interest, as it affords a ready means 

 of obtaining a chemically pure black lead, that by mechanical pressure 

 can be aggregated into a solid mass, and employed for those purposes 

 for which the best and most expensive plumbago has hitherto alone 

 been applicable. The outline of the process may be thus stated : the 

 impure plumbago is mingled with chlorate of potash, and then acted 

 upon by a mixture of nitric and sulphuric acids ; these not only give 

 rise to the evolution of gaseous chlorine compounds, but also dissolve 

 up and remove many of the impurities. The plumbago, thus obtained 

 in a pure form, is washed and heated. The result of the combined me- 

 chanical and chemical action of these operations is, that the plumbago 

 is so perfectly disintegrated as to be formed into light ftoculi, which 

 are capable of being blown away by the slightest current of air. In 

 this condition they are readily condensed into solid blocks by pres- 

 sure. 



ARTIFICIAL PRODUCTION OF ALCOHOL AND OTHER ORGANIC SUB- 

 STANCES. 



It is inevitable that the rapid progress of discovery should be inces- 

 santly upsetting our convictions, and disclosing the precipitation with 

 which our limitary boundaries have been erected. Until quite recently 

 there was no position which seemed more firmly established than that 

 which declared the boundary between the inorganic and organic to be 

 absolutely impassable. Although it was known that organic substan- 

 ces were composed of precisely the same elements as those abundantly 

 found in inorganic substances, it was affirmed that a radical distinction 

 existed, and defied the ingenuity of man to obliterate it. We could 

 analyze any organic substance into its elements ; but, having taken it 

 to pieces, we could not put these elements together again, so as to re- 



