666 Chronicles of Science. [Oct., 



nitride in a stream of hydrogen is of a silver- white colour, and so soft 

 that it may be cut with an ordinary knife. 



Before leaving the metals, we may mention a process for the pre- 

 paration of potassium, which the author, Beketoff,* thinks may be 

 applied to the commercial manufacture of the metal. He simply heats 

 hydrate of potassium and aluminium in a gun barrel. The process is 

 certainly extremely simple ; but while aluminium is only to be 

 obtained with the aid of sodium, it is not likely to be employed by a 

 manufacturer. 



Though scarcely belonging to Chemistry, we may place on record 

 here Mr. Gale's process for rendering gunpowder non-explosive for 

 storage and transport. The inventor simply mixes three or four parts 

 of finely-powdered glass with one part of the powder, and when the 

 latter is required for use the two are separated by means of a sieve. 



Some very useful papers on analytical chemistry have been published 

 since our last. The first we may notice has reference to the analysis 

 of waters,j and gives a method of arriving at the true composition of 

 the saline matters. The author first treats the dry residue several 

 times with boiling absolute alcohol, by which he separates the chlorides. 

 The residue is boiled in water, and this solution gives the soluble 

 sulphates. The residue, insoluble in water, may still contain sulphate 

 of lime, the amount of which may be calculated from the sulphuric 

 acid, while the excess of lime, magnesia, and iron found in a hydro- 

 chloric solution, may be calculated as carbonates. 



A residue insoluble in water and acids is sometimes also very 

 difficult of fusion, and chemists will thank Professor Bloxam for a 

 simple method^ of fluxing small quantities, which will save analysts 

 much trouble. The author prepares a mixture of one part of fine 

 charcoal and six parts of nitre. Five grains of the insoluble residue 

 to be examined, and ten grains of carbonate of soda, are mixed with 

 seventy grains of the deflagrating mixture, and a match is applied. 

 Deflagration and consequent fusion immediately take place. The 

 operation may be performed in a thin porcelain dish, or even on an 

 iron tray, for the metal will not be affected. It is sufficient to say 

 that the process answers with such refractory substances as quartz 

 sand, pipe-clay, and fluor spar. Chrome iron ore alone withstands 

 the treatment. 



In estimating alkalies it is necessary to convert nitrates into 

 chlorides. This is done by evaporating the nitrate with an excess 

 of hydrochloric acid. Dr. Leucanus§ finds that it requires the 

 repetition of the evaporation with acid several times to^ convert the 

 greater part of the nitrate into chloride. A small proportion of 

 nitrate, indeed, remains undecomposed after twelve evaporations. 

 The author therefore suggests igniting the nitrate with grape sugar 

 to convert it into carbonate, and extracting the alkali from the 

 carbonaceous residue with hydrochloric acid. 



* 'Zeitschrift fur Chem. uud Pharm.' New Series. Bd. 1, s. 376. 



t ' Chemical News,' vol. xii. p. 87. 



% 'Journal of the Chemical Society,' August, 1865. . 



§ ' Zeitschrift fur Analyt. Chem.,' Bd. iii. s. 403. 



