NOVEMBEE 15, 1912] 



SCIENCE 



665 



tific spirit, which carried him to Hofmann at 

 Berlin. Three papers were published by him 

 while at Berlin, the last being his disserta- 

 tion.° All dealt with earbonyl chloride and 

 its conduct with various amidines. This work 

 was interesting and possessed that normal im- 

 portance to the candidate for a degree; but 

 Loeb was not satisfied. That was in 1887. 

 The roving ardor of an awakening of physical 

 chemistry was in the air. It carried him to 

 Heidelberg and then to Leipzig to be with Ost- 

 wald, who had just made Arrhenius a real 

 power. 



By the advice of Ostwald, Loeb undertook 

 to study the molecular weight of iodine in its 

 solutions by the vapor-tension method.' His 

 experimental results led him to conclude: 



It seems very probable that iodine in its red 

 solutions has a molecular weight corresponding to 

 I4, whilst in the violet solution in carbon disul- 

 phide there is a less complex aggregation, giving 

 a value between I^ and I3. 



He found that the method of determining 

 molecular weights by the depression of the 

 freezing-point is preferable to the method by 

 vapor-tensions. He lacked a liquid which 

 would solidify and also dissolve iodine with a 

 pure violet color; but he endeavored to ob- 

 tain what corroborative evidence he could by 

 experimenting on the freezing-points of iodine 

 in acetic acid and in benzene, although he 

 was eventually forced to give up the attempt 

 by the very slight solubility of iodine in these 

 menstrua at low temperatures. The molecu- 

 lar weight of iodine as calculated from various 

 series of observations seemed to increase con- 

 tinuously with the concentration, so that there 

 was no point in the narrow limits between 



-These papers were: "Ueber die Einwirkung 

 von Phosgen auf Aethenyldiphenyldiamin, " Ber., 



18, 2427 (1885); "Ueber Amidinderivate, " lUd., 



19, 2340 (1886); "Das Phosgen vmd seine Ab- 

 kommlinge, nebst einigen Beitragen zu deren 

 Kenntnis, " Inaug. Dissert., 15 Marz I. Chem. 

 Labor, d. Berlin Univers. ; Chem. Centr., 58, 635 

 (1887). 



' ' ' Ueber den Molekularzustand des gelosten 

 Jods," Z. physikal. Chem., 2, 606; "The Molecu- 

 lar Weight of Iodine in Its Solutions," Trans. 

 Chem. Soc, 53, 805. 



extreme dilution and saturation at which the 

 molecular weight would appear constant and 

 could be accepted as trustworthy. This was 

 later confirmed by Paterno and ISTasini.* 



With the intention of testing the then 

 latest views on electrolysis, work in which 

 field he had begun with Gibbs, while still at 

 Leipzig, Loeb, with Nernst, carried on a 

 study of the kinetics of substances in solu- 

 tion." From determinations of Hittorf's ra- 

 tios of transference and the conductivity of a 

 number of silver salts, they calculated the 

 ionic velocity of silver, according to the prin- 

 ciples laid down by Kohlrauseh. The con- 

 stancy of the value obtained from observa- 

 tions with eight different salts gave satisfac- 

 tory evidence for the truth of the theory, the 

 numbers varying only within very narrow 

 limits. Loeb and Nernst also gave the calcu- 

 lated values for the velocities of the other 

 ions, and it further appeared from a compari- 

 son with the temperature coefficients of the 

 velocities that they decrease as the velocity in- 

 creases." 



Loeb then felt ready to come back to the 

 master who had changed his course in life and 

 to tell him what they were doing in Europe. 

 So in 1888-9 he returned as voluntary assist- 

 ant to Gibbs, who had retired from Cam- 

 bridge to his private laboratory at Newport. 

 After a year, Gibbs realized Loeb's power as 

 a teacher and made him go to Clark Univer- 

 sity as decent in chemistry. 



In a report on " Osmotic Pressure and the 

 Determination of Molecular Weights," ' Loeb 

 discussed Raoult's law, the matured papers of 

 van't Hoff on osmotic pressure, the measure- 

 ment of osmotic pressure, and the methods of 

 determining the molecular weight from the 



*Ber., 21, 2153. 



°"Zur Kinetik der in Losung befindlichen Kor- 

 per. Zweite Abhandlung. Ueberfiihrungszahlen 

 und Leitvermogen einiger Silbersalze von Morris 

 Loeb und W. Nernst, " Z. physikal. Chem., 2, 948. 



'Loeb also published in this year a paper on 

 the "Use of Aniline as an Absorbent of Cyanogen 

 in Gas Analysis," Trans. Chem. Soc, 53, 812 

 (1888). 



^ Am. Chem. Jour., 12, 130-5. 



