610 EXPERIMENT STATION KECOED. 



•• The improvemeuts in tbe iireseut metliod over ordinary methods of vacuum 

 desiccation are (a) the very rapid production of extreme vacua with the so- 

 called ' Geryk' type pump; (b) the freezing of the material prior to desiccation 

 to obviate primarily any concentration of substances, and to a lesser degree 

 shrinkage and hardening: (c) mixing of the sulphuric acid absorbent to prevent 

 saturation of its exposetl surface with its consequently greatly lessened efficiency. 



"The method affords a comparatively rai)id and exceedingly accurate means 

 for determining water in various materials, es])ecially such as can be frozen 

 solidly. Because of the friability and porosity of such dried materials, the 

 extract obtained by organic solvents can be secured with greater ease than by 

 the usual method of extracting oven-dried materials or those that have been 

 shriveled and hardened by ordinary methods of vacuum desiccation. 



" Liquids need not be frozen for determinations of water, but can be absorbed 

 on dry sand in proper containers. . . . 



" Experiments so far indicate that all materials, especially those unstal)le 

 substances ass»)ciated with immunity work, can be desiccated as outlined and 

 can be indefinitely preserved." 



Concerning' certain organic acids and acid anhydrids as standards in 

 alkalimetry and acidimetry, I. K. Phelps and L. H. Weed (Amer. Jour. Sci., 

 .'/, set:, 26 (1908), p. 138; Chcm. News, 100 (1909), No. 2588, pp. 3, .'/).— Suc- 

 cinic acid, succinic anhydrid, malonic acid, benzoic acid, phthalic auhydrid, 

 and phthalic acid were prei)ared in a pure state by methods described and their 

 efficiency tested as standards for alkalimetry and acidimetry. 



The authors conclude that these substances may well be used as standards. 

 For decinormal solutions of barium hydroxid they are even more accurate than 

 the gravimetric determination of the barium as barium suli)hate. In the pure 

 state they serve as well as the hydrochloric acid standard for alkalimetry and 

 acidimetry, but the authors recommend the use of the more soluble compounds, 

 that is, the succinic and malonic acids, although the less soluble ones furnish 

 equally accurate results. 



A change in the Kjeldahl nitrogen method, J. Skbellen, A. Brynildsen, 

 and O. Haavardsholm {Chcm. Ztg., 33 {1909). No.s: 87, p. 785; 88, pp. 795. 796. 

 fiff'S. 3). — The oxidation and digestion process is done with a s|)ecial kryj»tol 

 electric heating apparatus connected with the ordinary electric lighting sys- 

 tem. The current employed is 110 volts and 1.7 amperes, which heats the 

 tiask up to a temperature of 200° C. in about' 15 minutes, or the temperature 

 can be brought up higher in a little longer time. 



The usual method of hot distillation is dispensed with and Folin's recom- 

 mendation for taking out the ammonia by suction is followed. The process is 

 as follows: Two flasks, A and B, are necessary. A, which serves as a distill- 

 ing flask, is a Florence flask, fitted with 2 tubes, one of which dips in the fluid 

 to be distilled, and the other leads from the top of the bottle to the other 

 flask, B. The tubes and stoppers are all of glass and the stoppers ground in. 

 Flask B, which serves as the absorjition bottle, contains the normal acid and 

 is constructed on the same principle as flask A, from which it differs only in 

 being cylindrical, wide-mouthed, and smaller. When the apparatus is con- 

 nected air is aspirated through B for 2 hours, the amount of air going through 

 corresponding to about 100 liters. For the liberation of the ammonia the usual 

 sodium hydroxid is used with the addition of a little sodium sulphid. The 

 ai)paratus can be used alone or in series. 



Modified apparatus for estimation of nitrogen by the Kjeldahl process, 

 F. E. Weston and H. R. Ellis {Chevu News, 100 {1909), No. 2592. p. 50, 

 fig. 1). — A new form of Kjeldahl appai-atus is described, the chief features of 

 which are a bulb which prevents absorption of external ammonia, a thistle 



