CHEMISTRY. (CHEMICAL THEORY.) 



the case of other salts must be of the same order 

 of magnitude as that which had been found in the 

 case of tachhydrite. From the insolubility of 

 other sea salts in the mother liquor from which 

 tachhydrite separated, and the direction in which 

 pressure exerted an influence, it might be defi- 

 nitely concluded that the temperature of the 

 mother liquor when tachhydrite was deposited 

 was higher than 22.4 C. 



The chairman's address of James Lewis Howe 

 before the chemical section of the American As- 

 sociation, on The Eighth Group of the Periodic 

 System and Some of its Problems, concluded with 

 a brief consideration of the group from the theo- 

 retical point of view. Following Dr. Venable, the 

 author said that we may assume that each of the 

 first seven groups consists of a group element, 

 as, in group one, lithium; a type element, as 

 sodium; and two series, one of more positive ele- 

 ments, as potassium, rubidium, and ctesium, and 

 the other more negative, as copper, silver, and 

 gold. Further, the more positive the type metal, 

 the more closely will the metals of the positive 

 series resemble it. Thus, in the first group, the 

 positive series, potassium, rubidium, and caesium, 

 resemble the type element, sodium. In the sev- 

 enth group, the negative series, bromine and 

 iodine, resemble the type element, chlorine. Now, 

 the eighth group differs materially from the other 

 seven groups in that it contains three series, with 

 no group or type element. These three series are 

 transitional from the least positive among the 

 seven positive series, manganese, to the least 

 negative among the negative series, copper, ar- 

 senic, and gold. The properties of the metals of 

 group eight show the transition as from a chem- 

 ical point of view. Iron, cobalt, and nickel form 

 a direct gradation between manganese and cop- 

 per. Now conies a further question as to the pos- 

 sible transition elements between the most nega- 

 tive series, fluorine, chlorine, bromine, iodine, and 

 the most positive series, sodium, potassium, ru- 

 bidium, and caesium. From a theoretical point of 

 view such transitional elements should be neither 

 positive nor negative, and should have a valence 

 of zero. A few years ago the realization of such 

 a conclusion would have seemed impossible, yet 

 since the discovery of argon and its congeners it 

 seems almost probable that these places have been 

 filled in accordance with the theory. Taking 

 the most commonly accepted atomic weights, we 

 find helium preceding lithium, neon following 

 fluorine and preceding sodium, and argon really 

 between chlorine and potassium, but with an 

 atomic weight apparently slightly greater than 

 that of potassium, which follows it, resembling in 

 this respect cobalt and nickel of this same group, 

 and also tellurium and iodine. There would, in 

 addition, be expected from the analogies of group 

 eight one, two, and three transitional elements 

 between bromine and rubidium of atomic weight 

 80 to 85, and Ramsay has suggested that krypton 

 may belong to this place; so also an element or 

 elements of similar character might be expected 

 between iodine and caesium with atomic weight of 

 about 130. The recently published work of Laden- 

 burg and Kruegel on krypton gives it an atomic 

 weight of about 59. This would, as Prof. Laden- 

 burg suggests, make it immediately precede cop- 

 per; but unless we change very materially our 

 ideas of the periodic law, it is difficult to conceive 

 of an element with the properties of krypton lying 

 between nickel and copper. If these inert gases 

 belong to the eighth group it may seem strange 

 that iron and the other familiar metals which 

 belong here should be so unlike such a type ele- 

 ment aa argon or neon; it must, however, be 



borne in mind that this is only an expected exag- 

 geration of the departure found in the first and 

 seventh groups, where copper departs from its 

 type element, sodium, and manganese from its 

 type element, chlorine. As to whether three ele- 

 ments are expected of atomic weight 150 between 

 the light and the heavy platinum metals, we have 

 little data upon which to theorize. As a matter 

 of fact, there is very little definite knowledge of 

 the metals between caesium and tantalum. The 

 inter-Jovian planet proved to be an indefinitely 

 large number of asteroids; Sir William Crooke's 

 study of the rare earths leads him to the con- 

 ception of a group of asteroidal meta-elements in 

 the vacant space of the periodic table. We must 

 await further knowledge before these problems 

 can be satisfactorily solved. 



The existence of a relation between the differ- 

 ent factors of equilibrium (temperature, electro- 

 motive force, pressure, physical, and chemical na- 

 ture, condensation, and concentration) is affirmed 

 by M. O. Boudouard. This relation is such that 

 each of the factors is a function, and a continuous 

 function, of the others. This is known exactly in 

 the law which concerns the correlation changes of 

 pressure and temperature (Clapeyron's formula). 

 There exists further at constant pressure and tem- 

 perature a relation between the proportions of 

 different bodies present in a gaseous mixture in 

 equilibrium (Isembart's experiments in ammoni- 

 um sulphate). 



Mr. W. J. Pope, in a paper on recent develop- 

 ments in stereo-chemistry, read at the last meeting 

 of the British Association, reviewed the results of 

 investigation in that branch since the hypothesis 

 of the asymmetric carbon atom was first put for- 

 ward by Van t' Hoff and Le Bel in 1874. Pope 

 and Peachey prepared in 1899 a series of compounds 

 -which owed their optical activity to their contain- 

 ing asymmetric nitrogen atoms; and during the 

 present year they had prepared optically active 

 compounds containing asymmetric tin and sulphur 

 atoms. In the discussion of the paper, Dr. Divers 

 commented upon the light thrown upon the atomic 

 theory by this work. Dr. H. E. Armstrong ob- 

 served that considerable elucidation of the difficult 

 question of valency might be expected from it. 



The report of a committee on alloys of the 

 British Association mentions the fact of the belief 

 of most students that certain definite chemical 

 compounds exist in alloys. To prove this, how- 

 ever, special means had to be devised to detect 

 these compounds. Ordinary chemical methods of 

 isolation were of little use under the circum- 

 stances. Fractional solution has been effective in 

 some cases, and by means of it several distinct 

 metal compounds have been separated from al- 

 loys, such as platinum-tin, copper-tin, zinc-cop- 

 per, and other compounds. Another method is 

 by observation of the " freezing point." The 

 molten mixture is cooled down slowly, and the 

 temperature is noted at which solid matter begins 

 to appear from the liquid. This varies with the 

 proportions of the constituents, and by making 

 many observations with varying proportions a 

 curve may be obtained of their solidifying tem- 

 perature, any irregularity pointing to the forma- 

 tion of something more than a mere mixture. By 

 this means many interesting facts have been in- 

 dicated which have subsequently been rendered 

 evident by examination under the microscope. 

 Valuable and interesting results have thus been 

 obtained. Profs. Roozeboom and Chatelier hav- 

 ing particularly distinguished themselves in 

 this direction. A remarkable instance of peculiar- 

 ity is exhibited by mixtures of aluminum and 

 antimony, when all the mixtures freeze out at a 



