September 13, 1S94] 



NA TURE 



491 



dark bands subsequent to this stage are illusory, ami that they 

 are really the bright bands ; and what appear to be the bright 

 bands consist of overlaps which produce double the brightness 

 of the so-called dark bands. In reality, therefore, the bright 

 bands indicate the position of the dark bands. 



That by devices bands can be produced in a large tube 

 occupying only a small portion of the cross sectional area, at 

 any rate so far as the eye can discern. 



That, when employing Prof. Crookes' tubes for illustrating 

 experiments on radiant mailer, if suitable conditions are 

 observed, strirc are formed in these tubes. 



That, in tubes having exceedingly small electrodes, and 

 I apparently not capable of producing striae, these can be shown 

 ' to exist if very minute currents are employed. 



That the tube, when made to act as a condenser, permits 

 I more current to pass. 



That from the above considerations it is not unlikely that a 

 view, which has been held, in regard to the probable origin of 

 the bands, that they consist of a series of discharges through 

 the tube, is true ; that the nature of such discharge can be 

 varied by suitable devices placed within the tubes, and that the 

 examination of the nature of the discharge can be best made 

 with very minute currents, that is to say, currents so small that, j 

 if made any less, the tube would no longer show any sign of light. 



"The Asymmetrical Probability-Cure." By Dr. F. V. 

 Edgeworth. 



"On the Absorption Spectra of Dilute Solutions." Fjy 

 Thos. Ewan. 



In order to measure the extinction coefficients of verj- dilute 

 solutions, a new spectro-photometer was devised, in which a 

 Lummer and Brodhun photometric prism was used, and the 

 photometric measurements made by means of Abney s rotating 

 sector. 



The absorption spectra of dilute solutions of cupric sulphate, 

 chloride, bromide, and nitrate were found to be identical. 

 Solutions of cupric acetate absorb, for the same amount of 

 copper, more light than those of the other salts used. The 

 <lifference tends to disappear as the solutions become more 

 dilute, and it is increased by the addition of acetic acid. 



Measurements of the absorption spectra of a series of solu- 

 tions of dinitrophenol in pure water were made, from which 

 the amoums of the substance dissociated into ions were calcu- 

 lated, and found to be in very satisfactory agreement with those 

 calculated from the electrical conductivity of the solutions. 



The ferric hydroxide formed by the hydrolysis of ferric 

 chloride in aqueous solutions containing less than o'oo5 gramme 

 molecules of Fe CI3 per litre, was found to contain no chlorine. 

 The hydrolysis may therefore be represented most simply by 

 the equation FeClj + 3II0O ^ Fe(OH)3 + 3HCI. The de- 

 terminations of the quantity of colloid lerric hydroxide con- 

 tained in these solutions (made partly by the spectro-photo- 

 meter, partly by filtration through porous earthenware) showed 

 that the equilibrium does not take place in accordance with 

 the law of Guldberg and Waage, but agrees much better with 

 the modified form of the law due to Arrhenius, in which 

 account is taken of the electrolytic dissociation of the different 

 substances. 



Paris. 



Academy of Sciences, September 3. — M. Loewy in the 

 chair. — The marine laboratory of the museum at Tatihou I., 

 near Saint-Vaast-la-Hougue (Manche), by M. Edmond Perrier. 

 A description is given of the laboratory fittings and arrange- 

 ments, .-ind the work enabled to be done by its means. — On two 

 methods for the study of currents in open circuits and of dis- 

 placement currents in dielectrics and electrolytes. An abstract 

 of a memoir given by the author, M. de Nicolaiefi". Discs or 

 rings of dielectrics are, in the first method, supported by bifilar 

 suspension between the two poles of an electromagnet so that 

 the plane of the ring is at 45" to the axis of the electromagnet, 

 and centrally situated between the poles. The difference in the 

 displacements caused in constant and alternating fields of the 

 same strength is due to a secondary field set up by displace- 

 ment currents caused in alternating fields. Paraffin shows an 

 augmentation of 12 per cent, for a period of 930 per minute, 

 and 9 per cent, for 770 per minute. In the second method, 

 displacement currents in the rings are caused by the iron in the 

 magnet cores. The ring is suspended perpendicular to the axis 

 of the cores ; the polar faces are able to be brought nearer to or 

 removed fartlier from the parallel faces of the ring. By this 

 ; method, augmentations have been obtained of 15 per cent, for 



NO. I29S, VOL. 50] 



yellow wax, and S'3 per cent, for paraftin. Electrolytes in 

 annular glass tubes behave just like perfect dielectrics, sulphuric 

 acid giving an augmentation of deviation of 15 per cent. — 

 Assimilability of potash by the action of nitrates in poor 

 siliceous soils, by M. P. Pichard. It is shown that, in 

 presence of nitrates, a part of the potash combined with 

 silica is capable of being assimilated by various plants, 

 and hence that it is necessary lo determine the total potash 

 present in soils as well as that portion eliminaied by acids or 

 aqua regia when estimating the agricultural value of soils. — On 

 the construction of the circle derived from seven right lines or 

 defined by the equation O = Si'/jT,-' — X- + V- - R-, by M. 

 Paul Serret. — On a new gravimetric method for the estimation 

 of glucose, by M. Fernand Gaud. Cuprous oxide is obtained 

 in much the usual manner by reduction, but care is u>ed to 

 carry out the reduction below 100° by using a water-bath as 

 source of heat. The reduced suboxide is then weighed by 

 transferring the carefully-washed precipitate to a specific 

 gravity bottle, and filling up with boiled water and weighing. 

 The weight/ of the precipitate is given by the formula 

 P - V, d 



P = 





where P is the weight of the water and precipitate, V.. is the 

 volume of the flask at the temperature of experiment t, d\% the 

 specific gravity of water at the same temperature, and A is the 

 specific gravity of dry cuprous oxide 5 SSi. The quantities of 

 glucose corresponding to given amounts of cuprous oxide are as 

 follows: — lomg. of CuoO = 5'4i3 mg. of glucose ; 20 = 9761; 

 30 = I4'l97 ; 50 = 23036 ; 100 = 46 221 ; 200 = 9f047 ; 

 300 = 138 '842; 400 = 188928. — Phenomena following from 

 the dialysis of the cells of the beer ferment, by M. E. Onimus. 

 Yeast secretes a dialysable substance which inverts the sugar 

 present before new cells are produced. The medium is modi- 

 fied by the zymase, and then only becomes able to support the 

 production of new cells. — On the Constantinople earthquake of 

 July 10, 1S94, by M. D. Eginitis. The method of Dutton and 

 Hayden gives the focus at a depth of 34 km. The speed with 

 which the shock travelled to various places is as follows : — 

 Paris, 3 km. ; Pavlovsk, 3 '5 km. ; and Bucharest, 3 '5 km. per 

 second. 



Berlin. 



Physiological Society, July 6. — Prof. Munk, President, in 

 the chair. ^Dr. J. Munk had tested the results of his experi- 

 ments on fasting man by further new experiments on dogs, with 

 the special object of investigating the excretion of chlorine, 

 phosphorus, lime and magnesia, which he had found lo be in- 

 creased in man during hunger. During ten days of fasting he 

 found all four of the above substances, but especially phosphorus 

 and lime, in largely increased quantities in the urine, as com- 

 pared with days of normal dieting. The fa;ces also during 

 hunger, which closely resembled meconium both in appearance 

 and composition, contained an increased amount of phosphorus, 

 lime, and magnesia. By calculating, from the amount of 

 nitrogen excreted, the amount of body-proteid metabolised 

 during hunger, he found that only a portion of the excreted 

 phosphorus could have come from the proteid ; the remainder 

 must have resultel from the metabolism of some constituent of 

 the body rich in phosphorus and lime. The ratio of these to 

 each other corresponded to a metabolism of bone-subslance 

 amounting to about 39 grms. in ten days of hunger. Dr. Munk 

 further reported on experiments on dogs, in which he at one 

 time administered a given amount of meat all at once, and at 

 another time the same amount ol meat distributed over three 

 meals. In the latter case the excretion of nitrogen in the urine 

 was greater than in the former, indicating a less perfect utilising 

 of the proteid. This result on dogs is, however, not applicable 

 to man, in whose c.ise the conditions are diflTerenl, and in whom, 

 as shown by Ranke's older experiments, a given amount of food 

 is more completely utilised if taken in separate portions than if 

 eaten all at once. — Dr. Engel gave an account of his observa- 

 tions on the blood-corpuscles of incubated hens-eggs, leading 

 to results essentially thesame as those obtained from mammalian 

 embryos. In birds the red and white corpuscles and platelets 

 take their origin from nucleated red cells. These views were 

 supported by photographs and microscopic preparations, which 

 were, however, regarded by Dr. Henda as not excluding the 

 possibility that the appearances they presented were purely 

 artificial. 



