410 



need only be manured with pliosphoric acid and potasli manures. 

 Trials with oats, bucicwlieat, sjjurry {Spcnjnla arrcnsis), and rai)c 

 seemed to indicate that these plants also fix nitrojj^en. The plants 

 were grown in glass jars filled cither with sandy or loam soil, to which 

 potash, phosphoric acid, aud lime were liberally applied. The ])er- 

 centages of nitrogen in the soil before and after the experiment and in 

 the seed and harvested crop were determined. These figures as given 

 show that the nitrogen contained in tlie oat croj) was 34.3 times, that 

 in the buckwheat croj) 11.0 times, that in the spurry times, and that 

 in the rape crop 114.2 times that sui)plied in the seed. The i)ercentage 

 of nitrogen contained in the soil at the end of the experiment was in 

 every case slightly in excess of that contained before the experiment, 

 indicating that the soil had not been depleted in nitrogen by the crop- 

 ping. The author assumes that the nitrogen acquired by the plants 

 was derived from the atmosphere, and without the aid of symbiosis 

 with lower organisms. 



A new reagent for albumen, J. S. MacWilliam {Rev. intern, ties 

 fahitic. 4, 212; Chem. Centralbl., 18.91, part 2, p. 590). — Sul])ho-salicylic 

 acid is said to give in absolution of 1 part of albumen in i()(),Ot)0 a pre- 

 cipitate which is free from urates, phospluites, alkaloids, etc. The 

 reagent is prepared by heating concentrated sulpliuric acid with salicylic 

 acid, allowing the sulpho-salicylic acid to crystallize out, and then 

 recrystallizing from hot water at 120° F. In making the test the solu- 

 tion to be tested is strongly acidulated, 1 or 2 drops of the saturated 

 aqueous solution of sulpho-salicylic acid added, and the solution shaken. 

 The apx)earance of a cloudiness or a i)recipitate in a few seconds 

 indicates the presence of albumen. If the precipitate is dissolved by 

 heating and reappears on cooling, pei>tones are present. 



Fat extraction and fat calculation in milk analysis, P. Vieth 



{Analyst, 1891, pp. 203-208). — In a paper on this subject read before 

 the Society of Public Analysts, London, the author expressed the 

 belief that the practical value of a mathematical formula expressing 

 the relation between the specific gravity, total solids, and fat in milk is 

 now very generally acknowledged by analytical chemists who i)ay more 

 than a superficial attention to milk analysis. The more frequently such 

 a fornuila is proved to be in accordance with the actual facts the more 

 confidently will it b'e employed and the more useful will it become. 

 In the laboratory under his charge (that of the Aylesbury Dairy 

 Comp'iny, London), Avhere about 18,0(K) samples of milk are examined 

 annually, the percentage of fat in the bulk of tlie samples is calculated 

 from the specific gravity and jiercentage of total solids. But gravi- 

 metric fat determinations are made continually, so that the results 

 ol>tained by analysis have been compared in a large number of cases with 

 those obtained by calculation. In these calculations, the Fleischmann 

 formula is used where the solids are determined by drying the milk on 



