'ULY 11, 1919] 



SCIENCE 



49 



sulphuretted hydrogen and to coagulate the sul- 

 phur. After filtration, the solution can be made 

 up to a given volume, and an aliquot portion taken 

 for comparison of the color produced by addition 

 of hydrogen peroxide, ■with that of a standard 

 titanium solution. Or, the titanium may be pre- 

 cipitated Tvith eupferrou, and the precipitate 

 burned and weighed as titanium oxide. A standard 

 magnetite of the Bureau of Standards containing 

 0.99 per cent. TiO^ was analyzed, and the results 

 were within a few hundredths of a per cent, of 

 that given. Concordant results were also obtained 

 with an ore containing between thirteen and four- 

 teen per cent, of TiO,. Fusion of the ore with 

 borax in a platinum crucible also gave satisfactory 

 results, the disintegration of the fused mass being 

 however not so rapid as when sodium peroxide was 

 used. 



The calculation of the efficiency of the silent 

 discharge process for nitrogen fixation: F. O. 

 Anderegg. Oxygen combines with nitrogen in the 

 silent discharge. The discharge evidently changes 

 the comparatively inert molecule into a more active 

 condition which is probably atomic. The energy 

 required for this activation is all that is necessary 

 for the fixation of nitrogen. The splitting up of 

 the molecules is probably the result of electrons, 

 which have acquired a suitable velocity by falling 

 through a minimum potential gradient colliding 

 with the oxygen or nitrogen molecules. To cal- 

 culate this energy of activation of oxygen use 

 may be made of the fact that ultra-violet light of 

 a wave-length shorter than 190 nfi, is completely ab- 

 sorbed by oxygen with ozone being formed. This 

 corresponds to a potential gradient of about 6.4 

 volts using the quantum theory. Then to activate 

 one mol of oxygen requires about 146 large calor- 

 ies. For nitrogen the wave-lengths have not been 

 similarly determined but the recent work of Davis 

 and Goueheri makes the value of 9 volts seem to 

 be a likely one. This corresponds to 207 calories 

 per mol. At ordinary temperatures in the silent 

 discharge the nitric oxide first formed is oxidized 

 not merely to tetroxide but, because of the excess 

 of ozone, to pentoxide, requiring one more active 

 oxygen for this step. The complete reaction for, 

 the formation of nitric acid anhydride is then 



2N(— 207) -f 20(— 146) +0, + 0(— 7.3) = 

 NA(+1.4) +427.4 calories. 



The numbers in brackets represent the values in 

 large calories required for the formation of the 



iPhys. Sev., 1.3, 1-5, 1919. 



substance from the ordinary molecular condition 

 of the elements. , On an efficiency basis this 

 amounts to about 250 grams of nitric acid per 

 kilowatt hour. This possible yield compares fav- 

 orably with the 134 grams obtainable from the 

 union of oxygen and nitrogen at 4,200° A. in the 

 purely thermal process. In practise a combina- 

 tion of the thermal and electrical process is used. 

 Similarly in the formation of ozone the limiting 

 yield is about 510 grams per kilowatt hour as com- 

 pared with 80-90 grams, the best results actually 

 obtained with an efficiency of 15-17 per cent. 



The viscosity of casein solution — I., the effect of 

 p • Harper F. Zollek. The study of the viscos- 

 ity of casein in alkaline solutions was taken up 

 with the ultimate object of determining its chance 

 relationship to the adhesiveness of such solutions. 

 Viscosity curves of Hammarsten and Dairy Di- 

 vision caseins dissolved in sodium hydroxide show 

 a maximum viscosity in the region of 9.0 Ph- The 

 slope of the curve is very precipitous on either 

 side of the maximum. The hydrogen-ion concen- 

 tration was measured both colorimetrically and 

 electrometrically ; the Clark electrode-vessel being 

 employed for the latter determinations. A great 

 significance is attached to the flattening of the 

 viscosity curves immediately following the decline 

 from the maximum. This is intimately correlated 

 with the alkaline hydrolysis and evolution of am- 

 monia in this zone. Sohitions of casein in am- 

 monia do not exhibit the precipitous decline from 

 the maximum viscosity, although the maximum is 

 in the same narrow region of Ph. The observa- 

 tions of Sakur, Pauli, Chick and Martin and Rob- 

 ertson were reviewed. 



Periodic viirations in gels: J. M. Johlin. 



Boiling point of liquids: F. P. Soebel. Basing 

 his deductions on the assumption that at the boil- 

 ing point of a liquid the vibratory energy of in- 

 dividual molecular constituents of the liquid and 

 of its vapor must be equal, the author finds that 

 the absolute temperature Tx of the boiling point 

 of an absolutely pure liquid is expressible as 



_ _ mp^vx 



"~ Tig" 



in which formula m represents the molecular weight 

 of the substance or compound and Px and Vx the 

 pressure and volume of the vapor at the tempera- 

 ture Tx- For ordinary liquids containing impuri- 

 ties lowering the boiling point, the above equation 

 reads, 



rp ^ (PzVx - C)m . 

 2 



