AGRICULTURAL CHEMISTRY AGROTECHNY. 215 



moderately low temperatures 4 to 9 days bad from 0.014 to 0.01!) per cent, 

 \vhil(> those stored for over a year were even higher. 



The determination of the acid value of crude fat and its application in the 

 detection of ag'ed foods, M. E. Pennington and J. S. Hkpiu'un {Jour. Awcr. 

 Chrni. S'lC, 32 {1910), No. Jf, pp. 56S-572). — The authors recommend determin- 

 ing the acidity of the crude fat (I'endered in the laboratory) as an index for 

 ascei'taining the age of chicken meat. It is stated that the acidity of the 

 visceral fat Increases more markedly wMth the time of keeping or with bad 

 handling than does the subcutaneous fat. Rendering the fat in the laboratory 

 takes a much shorter time than the modified official extraction method, and the 

 results are practically as accurate. 



Analyses of dai-k colored vegetable fat residues, C. Stiepel (Scifensiedcr 

 Ztf]., SO {l!iO<J), p. 1199: ahfi. in Ztschr. An()Cir. Chcm., 23 {1910), No. 9, pp. 

 .'i21, Ji28). — The author explains that the difficulty experienced in the analysis 

 of vegetable fats for the saponification number, free fatty acids, and neutral 

 fats is due to the fact that the ether-soluble nonfatty substances have a tend- 

 ency at higher temperatures to bind large amounts of free alkali which finally 

 enter into the calculation as fat. The author proposes a method which elimi- 

 nates this tendency to error. 



The determination of total sulphur in organic matter, H. Schreiber ( U. 8. 

 Dept. Agr., Bur. Chein. Circ. 56, pp. 9). — Probably only two of the many methods 

 proposed, namely, the Barlow-ToUens, or absolute method, and the Osborne, or 

 peroxid method, are deemed either easy to manipulate or accurate. The latter 

 leaves much to be desired when used for solid material. A new method is 

 described, as follows: 



Weigh 1 gm. of material in a 100 cc. nickel crucible, add 10 cc. of a solution 

 made by dissolving 100 gm. of sodium nitrate and 150 gm. of sodium hydrate 

 in 500 cc. of water, then 5 gm. of crystallized magnesium nitrate, and stir with 

 a platinum rod, thoroughly mix and see that the sample is broken up as much 

 as possible. Wash down the material adhering to the stirring rod and sides 

 of the crucible with the smallest possible amount of water. (The addition of 

 much water will i)roloug the subsequent heating unnecessarily.) Heat for one 

 liour on a hot plate covered with a thin sheet of asbestos paper at about a tem- 

 I)erature of 130° C. Cover the crucible, so tilting it as to leave an opening for 

 the steam to escape and heat further for one hour at from 150 to 160°, or until 

 the material is entirely dry. If the fusions begin to bump, lower the heat so 

 that the covers will not be jarred down tight on the crucibles and the material 

 lost by frothing. When the mass is entirely dry, put the covers on tight and 

 heat gradually to 180°, then for 35 minutes at about 180 to 200°. 



Set the crucible (with the cover on tight) into a round hole in a piece of 

 asbestos board, so that about 1.5 in. of the lower part of the crucible shall pro- 

 ject l)elow the asbestos board, which is to be laid flat. Heat with the Bunsen 

 burner 2 hour, allowing the flame to just touch the bottom of the crucible dur- 

 ing the first 15 minutes, and then with the full heat during the last 15 minutes, 

 (Never let the inner cone of the Bunsen burner strike the crucible.) During 

 the first 5 minutes of heating with the full flame keep the crucible in an up- 

 right position, then remove the cover and so tilt the crucible as to fuse any 

 material which may have crept up the sides. Ret-urn the crucible to the 

 upright position, cover, and heat for 5 minutes more. When solidified, and 

 before it has entirely cooled, place the crucible in a GOO cc. beaker with 150 cc. 

 of distilled water and cover. Put the crucible cover also in the be;iker, slightly 

 rotate and so tilt tlie beaker that all jiarts of the crucible shall touch the water. 

 Run in 1.3 cc. of hydrochloric acid (sptx-ific gravity I.IH) from a burette and 

 again rotate the brealcer slightly. Tip the crucible so that the other side comes 



