November 30, 1905 J 



NA TURE 



117 



Nitrocellulose. 



D= 



D=o's 

 2835° 

 ?«5 



D=o'45 D=0-4O D=o'35 D=o-30 



4305° 4007° 3630° 3320° 3060" 



3954 1S00 S79S 3°7° 3530 



D=oi 3 D=o'io D=oo 5 



268o° 2520° 2400 J 



1345 3*95 3*55 



If these figures be examined, it will be noted that in 

 each explosive at the higher densities the temperatures 

 obtained by the two methods are nearly identical, those 

 determined from equation (i) being the higher, but as the 

 density of charge is decreased the difference at the very- 

 low densities is remarkable ; some of this difference is 

 doubtless attributable to the slow burning under feeble 

 pressures, and to the rapid cooling, by communication of 

 heat to the walls of the explosive vessel during the ignition 

 of the charge, but it is impossible to ascribe the whole 

 difference to this cause, and the author can only suggest that 

 the explanation is to be sought in the probable dissociation 

 of the carbonic anhydride and aqueous vapour at low 

 pressures, this dissociation being prevented wholly or 

 partially by the very high pressures at the higher densities. 



Various substances such as carbon, metallic platinum, 

 tantalum, osmium, and titanium have been placed in the 

 charge, and all have been more or less fused and volatilised 

 during the small fraction of a second to which they were 

 exposed to the maximum heat. 



A great part of the titanium was recovered in a fused 

 crystalline condition. 



Osmium and thin platinum foil were volatilised, and 

 thick sheet platinum was recovered in the form of a button. 



Received October 6. — " On the Isolation of the Infecting 

 Organism (' Zoochlorella ') of Convoluta roscoffensis." By 

 F. Keeble and Dr. F. W. Gamble. Communicated by 

 Prof. S. J. Hickson, F.R.S. 



The authors have obtained experimental proof that the 

 green cells (Zoochlorella;) which occur in the superficial 

 tissues of the turbellarian Convoluta roscoffensis arise in 

 the body as the result of an infection. 



Like those of previous investigators (Haberlandt), the 

 authors' attempts to cultivate the green cells isolated from 

 the animal have failed. Indeed, the evidence points to 

 the conclusion that the green cells, once having entered 

 into th» body of the animal, lose all power of separate 

 existence. Therefore, in order to solve the problem of 

 the nature of the green cells, the authors were compelled to 

 attack it at the other end, viz. to attempt to discover the 

 organism before its entrance into the body. 



From their observations on the normal course of appear- 

 ance of the green cells in the bodies of just-hatched Con- 

 voluta, the authors were led to expect that the precursors 

 of the green cells would be discovered on or in the capsules 

 in which the eggs of Convoluta are laid. This proved 

 to be the case. By the isolation of such capsules green 

 colonies of a motile organism were obtained, and the 

 organism was proved to have the power of infecting young, 

 colourless Convolutas, hatched under sterile conditions, and 

 of giving rise in these animals to green cells identical with 

 those which occur in the normal adult. 



The infecting organism is in its active state a unicellular 

 four-ciliate alga. It has a single basin-shaped chloroplast 

 occupying the greater part of the cell, an eccentrically 

 placed plate-like eye spot, and a large octagonal pyrenoid 

 at the posterior end of the body. The motile cells fre- 

 quently come to rest and surround themselves with a thick 

 striated wall. They may also in this resting stage undergo 

 vegetative division, giving rise to a " palmella " condition. 



These characters point to the membership of the infecting 

 organism with the Chlamydomonadinea;. 



Faraday Society, October 31. — Lord Kelvin, president, 

 in the chair. — Alternate current electrolysis : Prof. E. 

 Wilson. Experiments (Roy. Soc. Proc, vol. liv. p. 407) 

 made with platinum plates in dilute sulphuric acid show 

 that of the total energy supplied to the cell in a given 

 time, more is returned to the source when the frequency 

 is high than when it is low, the maximum coulombs being 

 of the order 00006 per sq. cm. in each case. If the 

 quantity of electricity be plotted coordinately with the 

 E.M.F. of electrolysis it is found that at the higher fre- 

 quency, for about the same maximum coulombs, the curve 



NO. 1883, VOL. 73] 



has relatively a smaller area, such reduction being prob- 

 ably brought about by the greater reversibility. An experi- 

 ment made at an intermediate frequency when the maxi- 

 mum coulombs were 0-0000023 per sq. cm. gave a still 

 higher value for the proportion of the total energy which 

 is returned to the source, demonstrating that the magni- 

 tude of the maximum coulombs has an important effect. 

 When a metal is dissolved in an electrolyte by alternate- 

 current electrolysis, the amount dissolved in a given time 

 at a given current density is smaller at high than at low 

 frequency. Besides this chief conclusion there are indica- 

 tions of other important effects. A complete investigation 

 would need to take accounts of the density and temperature 

 of the electrolyte, and possibly of other conditions. — 

 Alternate current electrolysis as shown by oscillograph 

 records : W. R. Cooper. Although polarisation is of the 

 nature of capacity in an alternate current circuit, there is 

 a considerable difference. What might be termed the 

 E.M.F. of a condenser rises and falls as rapidly as the 

 applied pressure, but although the E.M.F. of polarisation 

 may rise as rapidly as the applied pressure, it falls more 

 slowly, with the result that under suitable conditions the 

 current curve may depart very considerably from the sine 

 form. Actual oscillograph records are reproduced in sup- 

 port of this view. In considering the subject it has been 

 very generally assumed that the current follows a sine 

 curve. Since the curve obtained depends very much on 

 the conditions of the experiment, it is necessary to define 

 the conditions very carefully before conclusions can be 

 drawn from different experiments. Oscillograph records 

 of electrolytic rectification were also shown. — Note on the 

 crystalline structure of electro-deposited copper : Prof. 

 A. K. Huntington. In Mr. Cowper-Coles's process for 

 making copper wire electrolytically a spiral scratch or groove 

 on the mandril causes the copper deposited on it to part so 

 easily that a long ribbon can be obtained. The author's 

 explanation is that the direction of the lines of crystallisa- 

 tion of an electro-deposited metal is the same as in a 

 casting made on surfaces having the same inclination, i.e. 

 the crystals form at right angles to the surface on which 

 the deposit or the casting is made. — Some observations 

 respecting the relation of stability to electrochemical 

 efficiency in hypochlorite production : W. P. Dig by. The 

 author commenced by directing attention to the fact that 

 in all electrolytic methods of producing hypochlorite solu- 

 tions, only a small portion, rarely more than 18 per cent., 

 of the chlorine usually present in the form of chloride is 

 converted into hypochlorite ; and he suggested that the 

 amount of available chlorine produced from a sodium 

 chloride solution depends upon the relation which the 

 amount of unconverted sodium chloride actually present 

 between the electrodes bears to the current density. 



Entomological Society, November 1. — Mr. F. Menifield. 

 president, in the chair. — Exhibitions. — (1) Panurgus 

 morricei, Friese, a species of bee new to science taken 

 near Gibraltar, of which it was remarkable that, 

 whereas the species of this genus are wholly black, in 

 this species the c? face entirely, and the 9 partly, was 

 bright yellow, the legs partly yellow, and the abdomen 

 spotted down each side, somewhat as in Anthidium ; and (2) 

 the unique type specimen of Eriades fasciatus, Friese, a $ 

 of the Chelostoma group taken at Jericho in 1899, 

 in which again, while all its congeners are practically 

 unicolorous, the abdomen is brightly banded like a wasp : 

 Rev. F. D. Moi-ico. A discussion followed as to the 

 reason of the peculiar coloration in the species under 

 review, the exhibitor pointing out that the colour mimicry 

 in this species could not be due to parasitism, both 

 Panurgus and Eriades being industrious genera. — A <$ 

 specimen of the earwig Forficula auricularia taken 

 at Warwick in September last, with a drawing 

 of the cerci (forceps), which were very abnormal, the 

 broader basal part of the two appearing to be more or 

 less fused together, while the legs of the forceps also 

 were jointed to the basal part : W. J. Lucas. — Various 

 interesting insects from Guatemala recently received from 

 Sefior Rodriguez, including Heterosternus rodriguezi, 

 Cand., Pantodinus klugi, Burm., Plusiotis adelaida, Hope, 

 and a species of Orthopteron greatly resembling a dead 

 withered leaf, possibly a new species of Mimetica : G. C. 

 Champion. — Two species of Coleoptera new to the British: 



