504 



NATURE 



[June 8„ lyii 



poured, and an inner cylinder open top and bottom con- 

 taining a floating beaker to which a valve is connected. 

 When gas is passed into the inner cylinder through the 

 valve, the position of the floating beaker adjusts itself bo 

 that the pressure of gas rises until the valve just closet. 

 — Dr. W. C. McC. Lewi* : Internal, niolfcular, or intrinsic 

 pressure — a survey of the various expressions proposed for 

 Its determination. If we consider an imaginary plane of 

 unit area placed in any direction well inside a liquid mass, 

 equilibrium across this plane is maintained by the balanced 

 attractive and repulsive molecular forces, which we have 

 reason to believe arc of very great magnitude, amounting 

 to hundreds, or even thousands, of atmospheres. The 

 attractive force per unit area is drfined as the molecular, 

 internal, or intrinsic pressure of the liquid, and is usually 

 denoted by the symbol K. The present paper is a survey 

 of the various attempts which have been made to estimate 

 the value of K for various liquids. 



May 23. — Dr. R. T. Glazebrook, C.B., F.R.S., vice- 

 president, in the chair. — ^Dr. Arthur L. Day : Recent 

 advances in high-temperature gas thermometry. The 

 paper reviews the work done in recent years to increase 

 the range and accuracy of the temperature scale upon 

 which the various methods of measuring high temperatures 

 depend for their calibration. — Dr. J. A. Marker: I he high- 

 temperature equipment ot ihf National Physical Laboratory. 

 The paper dealt with thi mi iIukIs of construction and the use 

 of the various forms of apparatus for the attainment of 

 temperatures above 100° C. which have been designed at 

 the laboratory during the past ten years. — H. C. Qreen- 

 wfood : The boiling points of metals. In view of the 

 scanty and uncertain nature of our knowledge of tliese 

 important constants, a general investigation of the ques- 

 tion was greatly needed. The present experiments may be 

 divided into three sections : — (i) A study at atmospheric 

 pressure of the boiling points of a number of metals which 

 are unfiffected by carbon at high temperatures (antimony, 

 1440° C. ; bismuth, 1420° C. ; copper, 2310° C. ; lead, 

 1525^ ('. ; magnesium, 1120° C. ; silver, 1955° C. ; tin, 

 2275° C). (2) A study at atmospheric pressure of the 

 boiling points of some metals which readily combine with 

 carbon (aluminium, 1800° C. ; chromium, 2200° C. ; iron, 

 2450° C. ; manganese, 1900° C). (3) The influence of 

 pressures varying from 10 cm. of mercury to 50 atmo- 

 spheres on the boiling points of bismuth, copper, lead, 

 silver, tin, and zinc. — A. Blackie : The behaviour of silica 

 at high temperatures. This communication gives an 

 account of some experiments made to determine the effect 

 of heat on the strength and devitrification of the opaque 

 and transparent varieties of fused silica. A determination 

 was also made of their relative coefTicients of expansion at 

 high temperatures. — Prof. Max Bodenstein : Methods of 

 maintaining constant high temperatures. Three general 

 methods are in use : — (i) By means of a vapour in 

 equilibrium with its liquid. Suitable substances are only 

 available for a moderate range of temperature, but a 

 uniform temperature over a large volume is easily main- 

 tained. On the other hand, constancy of temperature over 

 a long peri(xl cannot be relied upon. (2) A liquid heating 

 bath controlled by a thermostat. For high temperatures 

 the method is restricted by the difficulty in obtaining a 

 suitable substance, although for moderate temperatures oil 

 <M- jjaratTin in a suitably constructed bath are fairly satis- 

 f irtorv, and temperatures up to 350° can be maintained 

 within 005° for several months if a sensitive gas regulator 

 be employed. (3) For high temperatures air baths only 

 can be employed. Tube furnaces heated electrically, either 

 directly or by means of coils, are now exclusively used, but 

 although a constant temperature is easily maintained, 

 uniformity of temperature is more difficult of attainment. 

 — M. Charles F«ry : Stellar pyrometry. The temperatures 

 of incandescent terrestrial bodies can be measured by refer- 

 ence to the laws of radiation, either the law of Stefan or 

 the law of monochromatic radiations, but these cannot be 

 applied in the case of stars, owing to the small amount of 

 radiation. The author has therefore devised an instrument, 

 based on Weiss's displacement law, according to which 

 temperature is measured by an appreciation of the colour 

 tint of the star. In the instrument described, the colour 

 of an image of the star is compared with that of a standard 

 lamp the tlnf of which can be varied. The pyrometer is 



NO. 2 171, VOL. 86] 



standardised by reference to an electric fun 

 (3500° C), and" the «un (0500' C). 



Royal Microtcopical Society, May 17. — Mi. 11. 1 

 Plimmer, F.R.S., president, in the chair. — J. V.. Barnard 

 .\ method of disintegrating bacteria and other '■ 

 The authcM- first mentioned that bacterial to 

 two kinds, extracellular and intracellular. i m- ii»rmeri 

 were excreted into the medium, e.g. beef broth, on wli 

 the organism was cultivated, so that by a proiess of filt 

 tion the organisms could be removed and the toxin wx 

 obtained in the filtrate, but the majority of p<^thoge 

 micro-organisms did not excrete their toxins, at least 

 any extent, and the toxins were retained within and form 

 integral parts of the cells of the organisms. One met 

 of obtaining these toxins was mechanically to disintegrafe 

 the bacterial cell, so that the cell contents were expre 

 and the apparatus described accomplished this. It 

 sisted essentially of a containing vessel in which, by 

 suitable rotation of steel balls, the organisms were crusfie 

 The principal conditions to be filled in such an appliar 

 were : — (i) approximately every cell should be brou£ 

 under the grinding action ; (2) little or no rise of tempera 

 ture should take place ; (3) the disintegration should 

 carried out in a vessel which was sealed so that, wh« 

 dealing with pathogenic organisms, none could escape 

 any stage of the process. These conditions were, in 

 main, complied with in the apparatus described. Exf 

 ments indicated that by this method the cell-juices we 

 obtained unaltered, and so were suitable for investigatic 

 on the chemical composition and properties of the bacteria 

 proteins and other cell constituents. .-Mso that, after tl 

 grinding process had been carried on for a sufficient tir 

 practically no cells remained which could be staine 

 properly by any recognised bacteriological method, 

 which, therefore, could be regarded as whole cells 

 taining a normal quantity of cell-juice. — ^James Murray; 

 Third portion of a Report on the rotifera observed by 

 Shackleton Polar Expedition of 1909. This portion of th^ 

 report dealt with the new species, &c., from the Pacif 

 Islands, in which the author said that in Fiji fifte 

 bdelloid rotifera were collected, in Hawaii twenty-four| 

 Ten species were common to the two groups. In Fiji 

 new species were distinguished, CalUdina pacifica ai 

 Habrotrocha nodosa, the latter previously known as 

 variety in India and elsewhere. In Hawaii there were 

 peculiar species, but some verj- distinct varieties, 

 various Pacific islands there have been recorded thirty -on 

 species of bdelloids. 



Zoological Society, May 23. — Dr. A. Smith Woodward, 

 F.R.S., vice-president, in the chair. — Dr. J. Stuarl 

 Thomson : .Alcyonaria of the Cape of Good Hope and 



Natal. The author dealt exclusively with the orda 

 Gorgonacea, and recorded nineteen species, of which sc 

 were described as new. — ^Dr. A. Hopewell Snilth and Dr, 

 H. W. Marett Time : Tooth-germs in the wallab] 

 {Macropus billardieri). The material upon which theil 

 observations were based had been kindly sent to thi 

 authors by Mr. Brooke Nicholls, of Melbourne. It cooi 

 sisted of three embryos of M. billardieri. The smalled 

 specimen (allowing for the difference in size of the adult] 

 of different species) was considerably younger than that ol 

 any other Diprotodont previously examined. In the upp 

 jaw they had identified six incisors, thus confirmir 

 M. F. Woodward's original statement. The functiona 

 incisors of the adult appeared to be the second, fourth, 

 sixth of the series. There were four premolars, of whid 

 the first, third, and fourth persisted. There was also on 

 molar tooth. In the lower jaw, owing to the difficulty 

 interpreting the conditions, it was not certain whetfaa 

 there were representatives of five or six teeth in front a 

 the premolars. Presuming there were five, the large fune 

 tional incisor of the adult was the fourth of the seriel 

 .\s in the upper jaw, there were four premolars and OH 

 molar, the second premolar not fully developing. TheCI 

 were evidences of vestigial predecessors to the large lowe 

 incisor and to pm*. The following points of histologic! 

 interest were noted : — (i) The heaping up of the epith'^liui 

 along the alveolar margins, a character often supt 

 be peculiar to the ungulates. (2) The precocious 

 mcnt of the enamel. (3) The compactness of thr ^i- ■.,. 



