108 EXPEEIMENT STATION RECORD. 



thin covering of wicking or muslin. This is fed with water from the reservoir 

 0. For convenience in adjusting as well as for cleaning and filling both bulbs 

 are provided with cocks, C and D. In order to present a convenient as well 

 as a large surface, B is made cylindrical. The bulbs A and B are connected 

 by the capillary tube E, partially filled with mercury. This tube is connected by 

 a T-joint, F, to a leveling bulb, or preferably to a cup and plunger, G and H, 

 by which the height of the mercury in the capillary may be adjusted. The cock 

 / serves to open or break communication between the capillary and the leveling 

 device. The bulbs J and K serve as mercury reservoirs and prevent accidental 

 emptying of the capillary and consequent interchange of the gases in A and B. 



" Electrical connection is made with the mercury by the sealed-in platinum 

 wire L. Another platinum wire, M, is sealed in in such a way that its fused 

 and smooth tip extends into the capillary at 7c. These wires are connected with 

 a battei-y and relay, and are spanned with a condenser and a by-pass in order 

 to eliminate sparking at the contact fc. 



" The opei*ation of the regulator is as follows : The whole instrument is placed 

 in a current of air whose humidity it is desired to regulate. Evaporation takes 

 place on the moist bulb B, producing a cooling of the inclosed gas. The con- 

 sequent reduction in pressure permits the excess pressure in A to drive the 

 mercury away from the platinum contact at fc. By this break in the circuit 

 the relay is released in such a way that there is actuated a steam or water 

 spray or a heating unit for raising the vaix)r tension of a body of water over 

 which the air flows. As the humidity of the air is thus increased, the evapora- 

 tion from B diminishes, and consequently the cooling. The pressure in B 

 therefore regains its former value and contact is again made at fc. the relay is 

 actuated, and the source of moisture is shut off. For laboratories having elec- 

 tric current it will probably be found convenient to raise the vapor pressure 

 by having the relay control an electric immersion heater plunged in a small 

 vessel of water, and to have this vessel kept at constant water level, as is the 

 Victor Meyer water bath." 



Fat analysis and fat chemistry in the year 1911, W. Fahrion (Ztschr. 

 Angew. Chem., 25 (1912), A^o. 18, pp. <S70-8S2 ) .— This is a review of the work 

 done in regard to the chemistry of fats during the year 1911. 



The density and solution volume of some proteins, Harriette Chick and 

 C. J. Martin (Bio-Chem. Jour., 7 {WIS), No. 1, pp. 92-96).— The density di- 

 rectly determined with dry specimens was from 5 to 8 per cent higher than 

 that calculated from the specific gravity of concentrated solutions in the case 

 of four proteins studied, showing the extent of shrinkage in volume occurring 

 when these proteins went into colloidal solution. 



The quantitative determination of aliphatic amino groups, II, D. D. Van 

 Slyke (Jour. Biol. Chem., 12 (1912), No. 2, pp. 275-28^, pi. 1, fig. i).— This 

 method (E. S. R., 26, p. 22), which has been employed in a great many investi- 

 gations, has been improved in that several new pieces of apparatus have been 

 introduced without increasing the cost or sacrificing any accuracy. 



Studies in regard to the solubility and decomposability of the nitrogenous 

 compounds present in the soil, J. Valmari (Abhandl. Agr. Wiss. Gesell. Fin- 

 land, 1912, No. 3, pp. 93). — As plants growing on moor soils rich in nitrogen 

 often require an addition of nitrogenous fertilizers, a measure of the nitrogen 

 present in such soils is something which is often desired. If this could be found 

 by investigating the nitrogenous compounds present in such soils and the con- 

 ditions under which they are soluble and decomposable, it would give a clew 

 as to the appropriate measures to stimulate those processes of mobilization 

 which occur in nature. 



