100 P. Mukerji — Method of detecting free Phosphorus. [No. 2, 



Hydrogen, Ether, &c. ; nascent Hydrogen has also a decisive superiority 

 as will appear later on. Then again on boiling Phosphorus in a complex 

 aqueous mixture (when the temperature must be higher than 100° G.) 

 some portion of the element may get oxidised by water if by nothing 

 else and cannot then be vaporised. 



As already stated some of the substances in presence of wbich 

 Phosphorus was detected by this method were such as are known to 

 interfere with the glow in the older methods. Milk, boiled rice, flour, 

 silica, though not included in this category were thus tried ; the glow 

 was well observed both at the jet and at the top of the middle tube after 

 addition of Phosphorus. Sodium or potassium hypophosphite solution 

 freshly prepared and filtered from particles of Phosphorus gave no glow, 

 though phosphoretted hydrogen was apparently evolved as the gas at 

 the jet burnt with a green core upon ignition : the glow appeared soon 

 after introduction of a minute piece of Phosphorus. Phosphoretted 

 hydrogen therefore does not interfere with the glow in this method. 

 Sodium phosphite also gave no glow though it evolved phosphoretted 

 hydrogen. Nitrous fumes are said to stop the glow of phosphorus, but 

 it was found that in this method nitrate or nitrate mixed with chloride 

 did not prevent the glow. Mustard oil was tried : it did not interfere 

 with the glow ; the jet became blocked by a whitish oily deposit after 

 some time, but there was the usual glow in the funnel (of the second form 

 of apparatus). The gas did not take fire and there was no explosion. 

 Sulphuretted hydrogen and also Iodine are stated to interfere with or 

 stop the glow of Phosphorus. In the present method the result 

 obtained in presence of either of these substances may be regarded as 

 satisfactory. In one experiment 10 c.c. of a saturated solution of Iodine 

 in potassium Iodide were introduced in three portions ; the glow was 

 seen as usual, and the issuing gas did not colour starch paper to any 

 appreciable degree. In another experiment about four-and-a-half 

 grammes of powdered ferrous sulphide were introduced in two portions, 

 and about 3 mgr. of Phosphorus were used. The glow was observed 

 at the jet and in the funnel : next the jet was changed and the new jet 

 also gave the glow. Ether, alcohol, and oil of turpentine were also 

 tried. Oil of turpentine stopped the glow altogether ; but it was found 

 that so far as the present method is concerned, the failure may be 

 easily remedied. A piece of Phosphorus, about 2 mgr., was introduced 

 into boiled rice ; oil of turpentine, 25 c.c., was next added and then a 

 little water, and the mixture shaken. Now the turpentine was removed 

 by decantation after adding some water ; the mixture was next quickly 

 washed (by decantation) with Alcohol and finally with water. The 

 mixture probably still contained traces of turpentine oil ; but on intro- 



