218 



SCIENCE 



[Vol. LV, No. 1417 



author and now used in the laboratories of The 

 Koppers Company. The tar is simultaneously 

 heated from above and cooled by a jacket of 

 liquid water about and below. The jacket water 

 is allowed to fall by evaporation, gradually 

 bringing more and more tar into the heated zone. 

 The manipulation is so simple the author finds it 

 difficult to believe that the method has not been 

 used before, but if so is unaware of such use. 

 The method permits the simultaneous approxi- 

 mate determination of light oil and water, 

 requires no new apparatus and practically no 

 attention, and handles efficiently very stiff tars 

 and tars of high water content. 



The arc rupture of liquid dielectrics: C. J. 

 BoDMAN. Various organic liquid dielectrics were 

 subjected to high frequency arcing. Finely 

 divided, highly non-conducting amorphous carbon, 

 saturated and unsaturated hydrocarbons lower in 

 the series, and a number of gases were obtained. 

 These gases consisted chiefly of hydrogen and 

 unsaturates with small amounts of carbon mon- 

 oxide, carbon dioxide, methane and nitrogen. 

 With au increase in molecular weight a slight 

 decrease in gas evolution per kilowatt seconds of 

 arc rupture was noted. With an increase of 

 halogenation a corresponding decrease in gas 

 evolution per kilowatt seconds arc rupture is 

 noted. Paraffine oils give approximately 60 c.c. 

 gas per kilowatt seconds. The liquid dielectrics 

 are apparently broken down by a temperature 

 pressure effect of very short duration, rather 

 than by sympathetic vibration and rearrangement 

 of the compounds by high frequency alone. Direct 

 application of this data is found in the use of 

 compounded liquid dielectrics for transformers, 

 circuit breakers and fuses. 



The effects of waterproofing materials upon 

 the tensile strength of cotton yarn: H. P. Hol- 

 MAN and T. D. Jabsell. Two sizes of cotton 

 yarn used in the manufacture of high grade 

 cotton ducks, after treatment with numerous 

 waterproofing materials including commercial 

 preparations, individual substances and formulas 

 developed in the laboratory, were exposed to the 

 weather for one year to show the effects on ten- 

 sile strength. The tensile strength of the treated 

 yarn after one year's exposure was in most cases 

 greater tlian the strength of the untreated yarn 

 after one year's exposure. 



Special order on world's standardisation: 

 E. C. Bingham, chairman. The attitude of the 

 manufacturer of reagent chemicals toward world 

 standardization. The attitude of the dealers in 



chemicals. The attitude of the university users 

 of chemicals. The attitude of the technical users 

 of chemicals. The attitude of Great Britain and 

 Canada toward world standardization. The atti- 

 tude of the federal government. Discussion led 

 by Charles L. Eeese, W. A. Notes, B. L. Mur- 

 ray, B. F. Buttan, H. D. Hubbard and others. 

 The nature of acid mine water from coal mines 

 and the determination of acidity: W. A. Selviq 

 and W. C. Batclifp. Water from coal mines is 

 usually decidedly acid in character containing 

 free sulphuric acid and ferrous, ferric and alum- 

 inum sulphates in addition to sulphates of cal- 

 cium, magnesium, sodium and potassium together 

 with silica and usually some chlorides. On stand- 

 ing, dilution, aeration or warming insoluble iron 

 compounds tend to precipitate. The direct titra- 

 tion of free sulphuric acid of mine water with 

 standard alkali solutions in the presence of 

 methyl orange gives results much too high. 

 Methods of accurate determination of contents of 

 mine water are given. 



Tests of the iodine pentoxide indicator for oar- 

 h07i monoxide: S. H. Katz and J. J. Bloompield. 

 The iodine pentoxide or ' ' hoolamite ' ' indicator 

 for carbon monoxide is a small, rugged, portable 

 instrument for quickly and easily indicating the 

 presence of carbon monoxide and estimating its 

 concentration. Commerieial instruments were 

 tested for sensitivity and accuracy. Besults 

 showed that the instrument gives positively indi- 

 cations with .07 per cent, or more carbon mon- 

 oxide in air. With .15 per cent, carbon monoxide 

 in air, determinations ranged from .10 to .23 per 

 cent, with an average of .16. With higher con- 

 centrations, the variations were proportionally 

 about the same. Fresh activated charcoal re- 

 moves the following gases that tend to give inter- 

 ference: acetylene, ammonia, benzene, ether, 

 ethylene, gasoline, hydrogen chloride, hydrogen 

 sulphide, natural gas containing members higher 

 than methane, and water. The following gases 

 do not interfere: carbon dioxide, carbon tetra- 

 chloride, chlorine, methane, nitrogen peroxide, 

 phosgene, and sulfur dioxide. Determinations 

 are made in less than one minute and no skill 'a 

 required. The instrument should prove valuable 

 in testing air in mine rescue and recovery opera- 

 tions around blast furnaces, gas producers, water 

 gas plants, flue gases and other places where 

 carbon monoxide occurs. 



The Berrigan filter (By title) : Mr. Stark. 

 Charles L. Parsons, 



Secretary 



