1919] AGRICULTURAL 0HE1OBTBI — AGBOTE< II NY. 711 



Intermediates used in the preparation of photosensitizing dyes. — II, 

 Quaternary halids, C. H. Lund and L. EL Wise (Jour. Indus, and r.nyin. Chi in., 

 11 (1919), No. 5. pp. 458-460). 



Synthesis of photosensitizing dyes, pinaverdol and pinacyanol, L. E. Wise, 

 i: Q. Adams, J. K. Stewart, and C. H. Lund (Jour. Indus, and Ilnyin. Chem., 

 11 (1919), No. 5, pp. 460-46S, figs. 4). 



The determination of total nitrogen including nitric nitrogen, B. S. Davis- 

 son and J. T. Parsons (Jour. Indus, and l.nijin. Chan., 11 (IU19), No. 4, pp. 

 S06-311, fly. 1). — The authors, at the Ohio Experiment Station, report an investi- 

 gation of the suitability for studies in soil biology of various methods of deter- 

 mining total nitrogen, including nitric nitrogen, and descrbe a new method 

 which Is considered to be easy of manipulation and extremely accurate. 



The procedures designated as oflicial were found to be unsuitable for use in 

 soil biology investigations where large volumes of solutions must be employ id, 

 and the Ulsch method was found Inaccurate in the presence of much organic 

 matter. The method found most satisfactory involves a combination of the 

 method described by Allen l for nitric nitrogen with the method of Mitscher- 

 lich, Herz, and Merres (E. S. It., 21, p. 208) for total nitrogen, including 

 nitrates. The technique is as follows: 



The solution (200 cc. of soil extract) is placed in a 500 cc. Kjeldahl ilask 

 and sufficient 50 per cent NaOH added to make the solution N/10 in NaoH. 

 To the solution are added 4 drops of oil and 1 gm. of Devarda's alloy (60 

 mesh, made free from ammonia by heating to about 200* C. for 30 minutes), 

 and the tlask is connected with a digestion tower containing a column of glass 

 beads and 35 cc. of H;SO« (4:1). The solution is heated to boiling in mini- 

 mum time and kept boiling gently for 20 minutes, during which time the acid 

 in the tower just about reaches the boiling temperature. The flame is then 

 removed and the acid is allowed to suck back into the llask. After boiling the 

 solution a few minutes longer, the flame is removed and the tower is washed 

 four times with 25 cc. of distilled water, which is allowed to suck back Into 

 the flask. The solution is then evaporated to charring, 5 gm. of K 2 SO« added, 

 and the digestion continued for about an hour after becoming bluish. After 

 digestion a considerable excess of strong NaOH containing K 2 S or Na a S is 

 added and the ammonia distilled. 



It is suggested that the difficulty with foaming in fertilizers containing con- 

 Blderable insoluble organic matter may be avoided by beating the sample to 

 boiling with 50 cc. of water, filtering through a small nitrogen-free filter into 

 the Kjeldahl flask, and washing the residue and beaker several times with hot 

 water. After reduction of the soluble nitrates as described, the filter paper 

 with residue is added to the flask, together with 5 to 7 gm. of K 3 SO«, and the 

 mass digested. 



The results obtained by the use of this method are said to be extremely 

 accurate, as loss of gaseous nitrogen is prevented and the amount of Inter- 

 fering substances reduced by the use of dilute alkali and loss of ammonia is 

 guarded against by means of the absorption device. 



A method for the rapid reduction of potassium platinic chlorid, HOBSCH 

 (Oompt. Rend. Acad. Sei {Paris}, 168 {1919Y, No. S, pp. 167-169).— The method 

 consists essentially of the reduction of the potassium platinic chlorid to metallic 

 platinum by means of alcohol at boiling temperature in a platinum crucible. 

 The reduction takes place only in the presence Of platinum and with dilute 

 solutions of the salt. Formaldehyde reduces the salt more slowly and forms 



l Juur. Indus, and Engin. Chem., 7 (1'JIO), No. 0, pp. 521-5U9. 



