624 REPORT — 1897. 



were heated in a porcelain boat, inclosed in a porcelain tube, through which a 

 glass tube was passed, kept cool by a current of cold water (hot and cold tube). The 

 alloys were treated for different periods of time up to one hour, at temperatures 

 between 500° and 1100° C, in currents of different gases, air, carbonic oxide, 

 hydrogen, and water gas (carbonic oxide and hydrogen in about equal volumes) 

 heing used in successive experiments. 



In each case the whole or a part of the tellurium was sublimed and condensed 

 on the cold tube, but the sublimates in only one case contained a trace of gold, in 

 the other cases the whole of the gold being found still to remain in the boat. The 

 exception was when air was used as the atmosphere, the oxide of tellurium con- 

 densed on the cold tube in that case being found to contain 0'03 per cent, of the 

 total gold originally present. 



A second series of experiments on a tellurium ore from Western Australia con- 

 taining over 1,000 oz. of gold per ton gave similar results. 



The heavy losses incurred in roasting tellurides appear to be due in reality to 

 liquation, the entectic of gold and tellurium having a very low melting point, so 

 that some of it passes through the mass and soaks into the furnace bottom at tem^ 

 peratures below a red heat. 



3. The Behaviour of Lead and of some Lead Coi)ipounds towar'ds Sidjjhur 

 Dioxide. By H. C. Jenkins. 



4. The Vapour Tensions of Liquid Mixtures. 

 By Dr. W. L. Miller and T. R. Rosebrough. 



The Electrolytic Determination of Copper and Iron in Oysters. 

 By Dr. C. A. Kohn. 



6, The Nitro-Alcohols.^ By Louis Henry, Professor of Chemistry iii the 



" University of Louvain. 



The method of preparation used by the author consists in the condensation of 

 aldehydes with nitro-parafRns. The condensation takes place in the presence of 

 water and of an alkali. A noticeable disengagement of heat accompanies the 

 reaction. He found that the condensation of the nitro-paraflin -uith aldehyde is 

 dependent upon the presence of hydrogen atoms linked to the carbon atom holding 

 the nitro group, and it does not occur with the tertiary nitm-paraffins. The 

 capacity of condensation also varies with the number of hydrogen atoms existing 

 in the nitro-carbon chain. This capacity for condensation can be exercised either 

 completely or incompletely and gradually, replacing but one of the two hydrogen 

 atoms available at a time. The intensity of the reaction depend,- on the number 

 of hydrogen atoms and on the molecular weight not only of the aldehydes but of 

 the nitro-paraffins. It is greatest with formic aldehyde ; it is at its maximum 

 also in nitro-methane. 



All nitro-alcohols are colourless, and cannot be distilled at ordinary pressure ; 

 most of them are liquid, those are solid which are derived from poly-acid alcohols. 



CH,N03 



The existence of the grouping npQjr determines in these alcohols a special and 



intensely disagreeable odour ; the haloid derivatives of the nitro-paraffins possess, 



' See the Author's communications published in the Bulletin de V Academie royale 

 de Belgique, 1895, 1896, and 1897. 



