6l2 



NA TURE 



[October 17, 1901 



action, in which he quoted the experimental results of an in- 

 vestigation of the action of invertase on cane sugar ; these results 

 confirm the conclusion of previous workers that the action of 

 inversion does not follow the simple law of mass action, but the 

 author does not regard the action as independent of mass in- 

 fluence. He considers that the influence of mass in inversion 

 changes is restricted by some other and hitherto unrecognised 

 influence, and this he believes he has found in the time factor 

 of molecular change. In reply lo remarks by Prof. Reynolds 

 Green, the author stated that his results were not necessarily in 

 disaccord with those of Croft Hill. A paper was read by Prof. 

 E. A. Letts and Mr. R. F. Blake, on the chemical and 

 biological changes occurring during the treatment of sewage 

 by the so-called bacteria beds. A large portion of the unoxi- 

 dised nitrogen present in sewage disappears during the passage 

 of the .sewage through the so-called bacteria beds, and the 

 authors consider that this may be due either to escape of 

 the nitrogen in the gaseous state as free nitrogen or 

 possibly as oxides or to the passage of the nitrogen into the 

 tissues of animals or vegetables; both of these causes of loss 

 may operate at the same time. An examination of sewage 

 matter before and after passage through the beds showed that 

 in nearly all cases the amount of dissolved nitrogen present in 

 the sewage was greater after treatment than before, although, of 

 course, if free nitrogen were evolved, only a minute fraction of 

 it would remain dissolved in the sewage effluent. With respect 

 to the possible biological explanation of the loss, it is pointed 

 out that the sewage beds at Belfast and other places swaini with 

 minute insects (Podnra aqua/ica), and that species of worms are 

 also present ; these in feeding on the sewage undoubtedly cause 

 a loss of nitrogen. A paper was then read by Dr. S. Rideal 

 on humus and the so-called irreducible residue in bacterial 

 treatment of sewage, in which the results were detailed 

 of a number of analyses of the humus-like substance or so- 

 called irreducible residue produced in bacterial sewage beds. 

 It is shown that in this material the ratio of carbon to 

 nitrogen and the percentage of nitrogen in the organic matter 

 present are very nearly the same as in humus mould ; the con- 

 clusion is drawn that if sewage has undergone proper bacterial 

 fermentation the small quantity of peaiy deposit formed is of the 

 nature of humus and is practically inoffensive. In a paper on 

 sulphuric acid as a typhoid disinfectant, Dr. S. Rideal advocated 

 the use of sulphuric acid, either as such or in a more portable 

 form as sodium bisulphate, for destroying the Bacillus tyjtkosus 

 in potable waters or in drainage from isolation hospitals. Mr. 

 W. Ackroyd gave a paper on the inverse ratio of chlorine to 

 rainfall, in which it vvas shown that when the observation periods 

 are shortened to daily estimations of the chlorine, minimal 

 amounts of rainfall are marked by maximum contents of chlorine, 

 and vice versa. In a second paper, Mr. Ackroyd dealt with the 

 distribution of chlorine in Yorkshire. Mr. G. T. Beilby, in a 

 paper on the minute structure of metals, showed that the micro- 

 scopic examination of metallic surfaces has revealed that 

 metals occur in two forms, viz , as minute scales or 

 " spicules " (a) and as a transparent glass-like substance 

 {/'). The spicules do not vary much in size in the different 

 metals and have a diameter of 1/300 to 1/400 of a milli- 

 metre ; the form a passes into the form ii when the metal 

 is pressed or hammered, and all polished metallic surfaces are 

 covered with a thin layer of this transparent form as with a 

 lacquer or enamel. Prof. G. G. Henderson and Mr. G. T. 

 Beilby read a paper on the action of ammonia on metals at high 

 temperatures ; on exposing platinum, copper, gold, silver, iron, 

 nickel and cobalt to ammonia gas at 600' to 900" disintegration 

 of the metal occurs, whilst a large proportion of the ammonia 

 is decomposed into its elements. After the treatment the metal 

 shows 3 spongy or cellular structure, as if it had been rapidly 

 cooled whilst in a state of effervescence ; copper and iron rods 

 of a quarter of an inch diameter are penetrated to the centre by 

 the ammonia gas within half an hour, and copper exposed to 

 the action of ammonia gas for seven days al 800" falls to a fine 

 powder. Dr. VV. C. Anderson and Mr. G. Lean gave a paper 

 on aluminium-tin alloys, in which they show that these alloys 

 evolve hydrogen freely when placed in water ; the microscopic 

 examination of the water-corroded plates of alloy indicates that 

 contact action between the excess of tin and the aluminium-tin 

 compound is responsible for the spontaneous oxidation. Prof. Willy 

 Marckwald, of Berlin, gave a very interesting demonstration and 

 description of the properties of radium ; he had surmised, from 

 the work of P. and S. Curie, that the barium salt extracted 1 



from pitchblende contains the radium salt as an isomorphous 

 constituent, and that the process used by these workers for 

 separating a strongly radio-active salt from the barium compound 

 is probably similar lo that in use for isolating the constituents of 

 an isomorphous mixture. He therefore fractionally crystallised 

 the barium chloride prepared from pitchblende from water, and 

 found that pure barium chloride first separates and then a 

 material, probably the eutectic mixture, which is very rich in the 

 radio-active component. The most strongly radio-active fractions 

 have the power of immediately discharging a charged gold leaf 

 electroscope when at the distance of half a metre from the 

 latter and when preserved under colourless glass soon turn it 

 a deep brown colour. The radio-active substance is strongly 

 luminescent in a dark room, and on interposing the hand 

 between the preparation and a barium platino-cyanide screen, 

 the bones in the fingers are seen sharply delineated on 

 the screen. Prof. Marckwald also exhibited several prepara- 

 tions of so-called " phototropic " substances, compounds which 

 change colour on exposure to sunlight and recover their original 

 tint on preservation in a dark place ; he mentioned that the 

 rapidity of change in either direction is considerably influenced 

 by the temperature. Prof. A. Michael, of Boston, read papers 

 on the genesis of matter and on the process of substitution ; he 

 also contributed a paper on the three stereoisomeric cinnamic 

 acids, in which he claimed to have proved that these three' 

 i.somerides actually exist, that is, that one more isomeride exists 

 than can be accounted for by the van 't Hoff hypothesis as in- 

 terpreted by Wislicenus. Prof. G. G. Henderson and Mr. 

 Corstorphine read a paper on the condensation of benzil with 

 dibenzylkelone ; in this condensation a tetraphenylcyclopenteno- 

 lone is produced, and on heating it with red phosphorus and 

 hydriodic acid a mixture of tetraphenylcyclopentene and teira- 

 phenylcyclopentane is formed. Dr. Hodgkinson and Mr. 

 L. Limpach contributed a paper on some relations between 

 physical constants and constitution in benzenoid amines, 

 and Dr. G. Young gave a paper on the existence of 

 certain semicarbazides in more than one modification. Prof. 

 W. H. Perkin, jun., gave a brief outline of his work 

 on the synthetical formation of bridged rings. Prof. Joji 

 Sakurai.of Tokio, in a paper on some points in chemical education, 

 observed that in spite of the rapid progress made in chemistry 

 during the past fifteen years, chemical education seemed still to 

 be carried out in an inefficient and unsatisfactory manner. He 

 pleaded for the more extensive use of physical chemistry as an 

 educational agent, but wished to replace the ordinary name of 

 this branch of the subject by the more rational one of general 

 chemistry. Mr. W. Thomson contributed a paper on the detec- 

 tion and estimation of arsenic in beer and articles of food ; after 

 noting that arsenic is introduced into barley during the process of 

 malting owing to the employment of anthracite coal or coke 

 containing arsenic, he suggested that all beers in 50 c,c. of 

 which arsenic could be detected by any test whatever should be 

 condemned. In a report entitled "The Equilibrium Law as 

 Applied to Salt Separation and to the Formation of Oceanic Salt 

 Deposits," Dr. E. F. Armstrong gave an excellent j-t'siim<.' oi the 

 work of van 't Hoff and his pupils on the investigation of the 

 conditions attending the formation of the German deposits of 

 magnesium salts ; the report was illustrated by the aid of a 

 number of models. Dr. J. Gibson, in a paper on the electrolytic 

 conductivity of halogen acid solutions, detailed the results of 

 experiments which showed that halogen acid solutions of con- 

 centrations corresponding to a change of curvature of the electro- 

 lytic conductivity curve have altogether peculiar properties. Other 

 papers were read by Mr. P. J. Plartog, on the flame coloration 

 and spectrum of the nickel compounds, by Dr. Farmer, on the 

 methods of determining the hydrolytic dissociation of salts, and 

 by Dr. T. S. Patterson, on the influence of solvents on the 

 rotation of optically active compounds. 



ENGINEERING AT THE BRITISH 

 ASSOCIA TION. 

 CECTION G suffered badly at Glasgow, both in attendance 

 "~-^ and in the quality of the papers presented to it, from the 

 Engineering Congress which was held in the University 

 buildings during the preceding week ; many regular members of 

 the Section were absent, and several valuable papers which 

 would under ordinary circumstances have come to the Section 

 were read instead at one or other of the Congress sectional 

 meetings. On the opening day, after the presidential address, 



NO. 1668, VOL. 64] 



