698 



SCIENCE 



[Vol. LVI, No. 1459 



decolorize oils is given and the derelopment of 

 several different tests is indicated. The most sat- 

 isfactory testj however, is based on the reaction 

 between fuller 'a earth and pinene. Fuller 's earth 

 reacts vigorously with pinene to form polymerized 

 products with the development of a very large 

 amount of heat. The amount of temperature rise 

 is used as a measure of the efdcieney of the clays 

 and data is given to show the relation between 

 this pinene efficiency and the decolorizing power 

 of such clays. A discussion of the mechanism 

 of the reaction, the materials used and the appli- 

 cation of the test for laboratory and plant use 

 is indicated. 



Effect of certain physical and chemical proper- 

 ties of emulsifying agents on the stahility of oil- 

 water emulsions: Leon W. Parsons and Brian 

 Mead. This paper embodies further studies on 

 Nujol-water emulsions and a comparison of these 

 systems and commercial mineral oil emulsions. 

 The technique of investigating these emulsions, 

 making use of mierophotographic apparatus and 

 the ultra-microscope, is given. A study has been 

 made of the following factors of extreme im- 

 portance in connection with the stability of emul- 

 sions : Physical characteristics of emulsifying 

 agents ; effect of opposing emulsifying agents in 

 the same system; action of oil soluble colloids on 

 the emulsifying agents; and similarity between 

 behavior of soaps and of finely divided solids. 

 The importance of relative wetting of the differ- 

 ent phases by the emulsifying agent is empha- 

 sized and it has been found that several common 

 emulsifying agents give abnormal results with 

 regard to type of emulsions produced. This 

 latter observation has important bearing on the 

 mechanism of the behavior of soaps and finely 

 divided solids as emulsifying agents. Certain 

 parallelisms have been observed between the be- 

 ha^^or of the emulsifj'ing agents used for Nujol- 

 water systems and those present in commercial 

 oil emulsions. 



Engine experiment with high sulfur fuels: 

 Carl O. Johns. These experiments were eon- 

 ducted by Professor George Winchester, formerly 

 in charge of the Engine Eesearch Laboratory of 

 the Standard Oil Company of New Jersey. A 

 Hvid type of Diesel engine ("Thermoil") was 

 used. Several fuels were tested to ascertain the 

 effect of both free and organic sulfur. The runs 

 were continued for 384 hours. The fuels included 

 high sulfur Mexican crude and gas oil, and mix- 

 tures of these with a polymer oil containing about 

 ID per cent, of combined sulfur, or 10 per cent. 



of sulfur in the mixed fuel. The running time 

 for these fuels was 180 hours. The compression 

 in the engine reached 500 pounds. A run of 204 

 hours duration was made with kerosene contain- 

 ing 0.85 per cent, of free sulfur in solution. Fre- 

 quent examinations of the dismantled engine dis- 

 closed no eiadenees of corrosion, nor was the 

 copper tubing affected appreciably. Trouble was 

 encountered by the excessive formation of carbon 

 which deposited on the exhaust valve and clogged 

 the spray holes to the cylinders. 



Gasoline saved on government trucTcs due to 

 adjusting the carburetors hy gas analysis: G. W. 

 Jones and A. O. Fieldner. Carburetor adjust- 

 ments by exhaust gas analysis on 15 trucks, vary- 

 ing from 2y2 to 7% tons capacity, showed that 

 all but one were too richly adjusted for maximum 

 power and economy. The adjustments made gave 

 an increase of over 20 per cent, in mileage for 

 the first month after testing and 16 per cent, 

 increase for the second month. The OO2 indi- 

 cator used for making the adjustments while the 

 trucks were operated was found to be practical 

 and easily operated by the laymen inexperienced 

 in the handling of chemical apparatus. An aji- 

 alysis of the exhaust gas under the conditions 

 which the truck is operated gives aa absolute 

 indication of the carburetor adjustment and re- 

 moves all guess-work. By adjustment for maxi- 

 mum power and economy is meant the leanest 

 adjustment without reduction of power. 



Some factors affecting the accuracy of Sayholt 

 viscosity measurement and their control: P. E. 

 Klopsteg and W. H. Stannard. Without a 

 suitable form of automatic temperature control, 

 it is impossible to secure experimental conditions 

 which conform to A. S. T. M. specifications, 

 namely, that "the bath shall be held constant 

 within 0.25° F. (0.14° C) at such a temperature 

 as will maintain the desired temperature in the 

 standard oil tube." At any rate, the require- 

 ments can not be met with the form of bath 

 described in the specifications. In this paper, 

 the development is described of an electric heat- 

 ing and regulating device which at a temperature 

 of 212° F. (100° C.) will hold the bath tempera- 

 ture constant within 0.1° F. (.05° C.) through- 

 out an entire day's run without attention. Con- 

 ditions within the oil tube are also considered, 

 and it is shown that when the A. S. T. M. method 

 of stirring is followed, even Avith the bath tem- 

 perature very constant at 212° P., variations of 

 0.5° F. are observable on a sufficiently sensitive 

 stirring thermometer. A method of stirring is 



