148 



CHEMISTRY. (CHEMICAL PHYSICS.) 



mask a particular center in it, thereby making 

 it possible for the second organism actively to 

 affect the molecules at other centers. This case 

 corresponds to the removal of a ward from a 

 lock, and the consequent possibility of using a 

 simpler key. Fermentation being at bottom a 

 process of hydrocatalysis, the function of the 

 enzyme is to 'introduce water into the circuit of 

 change, or to establish a circuit in which hydro- 

 lytic changes can occur. Hence we may speak 

 of the substance fermented as the hydrolyte, of 

 the ferment as the hydrolyst, and of the products 

 of hydrolysis as the hydroschists. It is more 

 than probable that the products ordinarily ob- 

 tained are but end products of a series of changes, 

 and that only some of these are enzymic, while 

 others occur, as it were, naturally, and are partly 

 analytic and partly synthetic in character. Sym- 

 biosfs as distinguished from parasitism involves 

 the conception not only of the concurrent exist- 

 ence of organisms, but of their useful concur- 

 rence. 



Chemical Physics. In his address on the 

 Progress of Physical Chemistry before the chem- 

 ical section of the American Association for the 

 Advancement of Science Prof. Theodore W. Rich- 

 ards, after some general references to work con- 

 tinued during the year in stoichiometry, on solu- 

 tions, on molecular compounds, in electro-chem- 

 istry, and in the discovery of new elements by 

 means of physical instruments and operations, 

 spoke of some unpublished work on physico- 

 chemical problems which had been done in the 

 laboratory of Harvard University. Among them 

 were a series of measurements of the potentials 

 of galvanic cells composed of metallic plates 

 immersed in fused salts at high temperatures, in 

 which constant values, agreeing remarkably with 

 Nernst's formula, have been reached by Dr. Gor- 

 don; an attempt to verify Faraday's law (more 

 successful than had previously been done), by Mr. 

 Edward Collins; a series of careful measurements 

 of the potential of numerous reversible electrodes 

 with the temperature and a comprehensive re- 

 vision of Meyer's work on concentration cells, in- 

 volving amalgams of different strengths, by Mr. 

 ( G. N. Lewis; studies of the eccentricities of in- 

 version temperatures and of transition intervals 

 exhibited by the double sulphates of potassium 

 rand manganese, by Mr. F. R. Fraprie; determina- 

 tions of the solubilities of argentic halides in so- 

 .hltions of sodic thiosulphate, by Mr. Faber; ob- 

 servations of some cases in which the dissolving 

 of a solid in a solution caused a lowering instead 

 of .a .rise of the boiling point, by Messrs. Harring- 

 ton and Henderson; a careful determination of 

 the .melting point of crystallized Glauber's salt, 

 made by Mr. Churchill for the purpose of secur- 

 ing a .new fixed point for the standardizing of 

 thermometers; and a study of the causes of the 

 occlusion and the unequal release of gases by 

 the oxides of metals formed from the nitrates, 

 by the author. It became evident in the last 

 researdh that the excess of oxygen usually pres- 

 ent in the material under consideration has a 

 tendency to work its way out by a process of 

 dissociation and recombination which reminds 

 one of the old-fashioned explanation of elec- 

 trolysis. The nitrogen, not being able to escape 

 in this fashion, is retained. 



In the autumn of 1898 the production of liquid 

 hydrogen in manageable quantities having be- 

 come possible, its solidification under reduced 

 pressure was undertaken by Prof. James De- 

 war. The first experiments were made with 

 the apparatus devised by the author, consisting 

 of a small vacuum test tube placed in a larger 



vessel of the same kind, excess of hydrogen partly 

 filling the space between the two vessels, and 

 performing most of the evaporation relied upon 

 to conduct the experiment. This attempt was 

 not successful, partly on account of the need of 

 a larger supply of the liquid, and other problems 

 were attacked. Recurring subsequently to ex- 

 periments with liquid hydrogen, Mr. Dewar no- 

 ticed that there was almost invariably a slight 

 leak of air, which became apparent by its being 

 frozen into an air-snow in the interior of the 

 vessel, where it met the cold vapor of the hydro- 

 gen coming off. The effect of this slight air leak 

 on the liquid hydrogen when the pressure was 

 reduced below CO millimetres was to cause its 

 solidification into a white frothlike mass, like 

 frozen foam. To determine whether this mass 

 was really solid hydrogen or a sponge of solid 

 air containing the liquid hydrogen the author 

 devised another apparatus, operating with which 

 he observed, upon the required conditions of pres- 

 sure, a gradual accumulation of perfectly pure 

 liquid hydrogen in the inner tube, and eventually 

 a sudden passage of the liquid hydrogen sur- 

 rounding the outside of this tube into a solid 

 foamlike mass, almost filling the whole space. 

 The hydrogen in the inner tube not being visible 

 through this mass, the apparatus was turned 

 upside down, and no liquid flowed down the re- 

 versed tube. The hydrogen within it must there- 

 fore have been partly solidified. By the aid of 

 a strong light and continuing the exhaustion the 

 solid in the space between the tubes became less 

 opaque, and the material in the inner tube was 

 seen to be a transparent ice in the lower part, 

 while the surface looked frothy. This fact 

 prevented the solid density from being deter- 

 mined, but the maximum fluid density was ap- 

 proximately ascertained to be 0.086, the liquid at 

 its boiling point having the density 0.07. The 

 solid hydrogen melts when the pressure of the 

 saturated vapor reaches about 55 millimetres. 

 The mean temperature of the solid was found 

 to be 16 absolute ( 257 C.) under a pressure 

 of 35 millimetres. Its indicated melting point is 

 about 16 or 17 absolute (257 or 256 C.). 

 The foamlike appearance of the solid when pro- 

 duced in an ordinary vacuum is due to the small 

 density of the liquid, and to the fact that rapid 

 ebullition is substantially taking place in the 

 whole mass of liquid. Prof. Dewar assumes that 

 " the last doubt as to the possibility of solid 

 hydrogen having a metallic character has been 

 removed, and for the future hydrogen must be 

 classed among the nonmetallic elements." 



A mixture of marsh gas and air, in the most 

 explosive proportions, was introduced by H. 

 Couriot and J. Meunier into electric lamps dur- 

 ing incandescence by a method described in the 

 authors' paper. It was found that the incan- 

 descence of the filament was at once obscured 

 except at one point, where, in about a minute, 

 a rupture occurred with a faint spark. No ex- 

 plosion of the mixture of air and methane oc- 

 curred ; but that combustion had taken place was 

 shown by the production of water and carbon di- 

 oxide and the disappearance of inflammable gas 

 inside the lamp. Hence the spark which passed 

 the moment the filament was ruptured remained 

 without effect. It had previously been pointed 

 out that incandescent metallic threads are power- 

 less to caUse the explosion of the most explosive 

 mixtures; the same is the case with the lamp 

 filaments. 



An observation made by Henry J. H. Fenton 

 in 1876 on the influence which iron exerts upon 

 the oxidation of certain organic substances has 



