March 29, 1900] 



NA TURE 



529 



contact in the oiher arm. The circuit thus established works a 

 relay which inserts a resistance in the heating circuit, and thus 

 automatically reduces the temperature. The action is remark- 

 ably prompt, the regulating circuit being made and broken two 

 or three times per second. The temperature of the thermostat 

 remains constant to within i.xrVT)'h of a degree C. , even when 

 the surrounding temperature changes suddenly by some 12 

 degrees. — Explorations of the Albatross in the Pacific, (iii.), 

 by A. Agassiz. The deepest trawl haul yet made was made 

 about 75 miles east of Tonga-Tabu. It was at 4173 fathoms. 

 The bag brought up a number of large fragments of silicious 

 sponge, belonging probably to the genus Crateromorpha, which 

 had been obtained by the Challenger at depths of only 500 

 fathoms. The bottom consisted of light brown volcanic mud 

 mixed with radiolarians. — Illinois Gulch meteorite, by H. L. 

 Preston. This siderite was found in Montana last year, on the 

 bed rock about four feet below the surface. It weighs 2\ kilo- 

 grams, and consists of 92 5 per cent, iron, 67 per cent, nickel, 

 and traces of cobalt, silicon, phosphorus and carbon. It shows 

 no figures on etching, but greatly resembles the Morrodal sider- 

 ite of Norway. — The Silurian-Devonian boundary in North 

 America, by H. S. Williams. This first article deals with the 

 Chapman sandstone fauna. It must be regarded as the equiva- 

 lent of the topmost fauna of the Welsh Silurian system. This 

 classifies the Lower Helderberg formation in the Silurian 

 system. 



The Physical Review for January contains the first part of 

 a paper, by Prof. R. A. Fessenden, bearing the title of " A 

 determination of the nature of the electric and magnetic 

 quantities, and of the density and elasticity of the ether." — Mr. 

 B. E Moore, in the same number, deals with electrolytic polari- 

 sation ; and Mr. H. V. Carpenter with the comparison of two 

 self-inductances. 



SOCIETIES AND ACADEMIES. 



London. 



On the Influence of the 

 1 Bacteria." By Allan 



Royal Society, February i. 

 Temperature of Liquid Air 

 Macfadyen, .M D. 



The experiments of Dr. Horace T. Brown and Mr. Escombe 

 {Roy. Son. Proc. vol. 62, 1898, p. 160) have shown that no 

 appreciable influence is exerted upon the germinative power of 

 seeds when exposed for no hours to the temperature of liquid 

 air ( - 183° C. to - 192° C. ). The results were equally negative 

 in the recent experiments of Sir W. Thiselton-Dyer {ibid. vol. 

 65, 1899, p. 361), in which seeds survived exposure for upwards 

 of six hours to the temperature of liquid hydrogen ( - 250° C. 

 to - 252° C). 



I The following investigation on the influence of the tempera- 

 ture of liquid air on iiacteria was carried out at the suggestion 

 of Sir James Crichton Browne and Prof. Dewar. The necessary 

 facilities were most kindly given at the Royal Institution. The 

 experiments were conducted under the personal supervision of 

 Professor Dewar, and he has asked me to put the results on 

 record, although it must be acknowledged that the essential 

 features of the investigation are due to him. 



Ten organisms were used for the experiments, viz. : — B. typhosus, 

 R. coli communis, B. diptheriae. Spirillum cholerae Asiaticae, 

 B. proteus vulgaris, B. acidi Icutict, B. anthrcuis (sporing 

 culture), Staphylococcus pyogenes aureus, B. phosphoiescens and 

 Photoba.terium balticum. 



The cultures were simultaneously exposed to the temperature 

 of liquid air for twenty hours ( - 182^ C. to - 190° C. ). They 

 were then carefully thawed and examined. The results may be 

 briefly stated. In no in.stance, whether on solid or in liquid 

 media, could any impairment of the vitality of the micro- 

 organisms be detected. The fresh growths obtained from the 

 exposed tubes were normal in every respect, and the functional 

 activities of the bacteria were equally unaffected. The colon 

 bacillus produced its typical effects— such as the curdling of 

 milk, the fermentation of sugar and the production of indol ; the 

 Staphylococcus pyogenes aureus retained its pigment-producing 

 properties, and the anthrax spores their pathogenic action, on 

 animals. The photogenic bacteria preserved their normal 

 luminous properties. These photogenic properties are intimately 

 connected with the functional activities of the cells. The cells 

 emit light which is apparently produced by a chemical process 



NO. 1587, VOL. 61] 



of intracellular oxidation, and the phenomenon ceases with the 

 cessation of their activity. Thesex)rganisms therefore furnished 

 a very happy test of the influence of low temperatures on vital 

 phenomena. Their cultures, when cooled down in the liquid 

 air for twenty hours, became non-luminous, but on rethawing 

 the luminosity returned with unimpaired vigour as the cells 

 renewed their activity. Watery emulsions of the photogenic 

 bacteria, on immersion in liquid air for a few minutes, ceased to 

 emit light, but on withdrawal the luminosity reappeared in a 

 very short time. Strips of filter paper soaked in the watery 

 emulsions and brightly luminous were immer.sed directly in the 

 liquid air with similar results. The sudden cessation and rapid 

 renewal of the photogenic properties of the cells, despite the 

 extreme changes of temperature, was remarkable and striking. 



The above experiments show that bacteria may be cooled 

 down to - 190 C. for a period of twenty hours without losing 

 any of their vital properties. 



Further experiments are in progress with the above-mentioned, 

 and with other micro-organisms exposed to the temperature of 

 liquid air for still longer periods of time, as well as to that of 

 liquid hydrogen. These experiments will form the subject of a 

 future communication. 



March 15. — "The Theory of the Double Gamma Function.* 

 By E. W. Barnes, B. A.,- Fellow of Trinity College, Cambridge, 

 Communicated by Prof. A. R. Forsyth, Sc.D , F.R.S. 



Physical Society, March 23. —Prof. W. E Ayrton, F.R.S., 

 Vice President, in the chair. — A paper on some experiments 

 illustrating syntony was read by Mr. P. E. Shaw. The experi- 

 ments described in this paper have been devised for the purpose 

 of showing in a lecture-room the principles of magnetic space 

 telegraphy, the distance between the sending and receiving 

 circuits being about fifteen yards. A current flowing in a main 

 circuit was interrupted by a tuning-fork of 100 vibrations pei 

 second, and a fraction of the current was passed through the- 

 sending coil. The sending coil was placed in series with a coib 

 of adjustable self-induction, and the two coils were shunted with,, 

 a condenser of variable capacity. By suitable adjustments an 

 oscillation of frequency 400 could be maintained in the sending 

 circuit. The receiving coil was in series with a variable self- 

 induction and a variable capacity, and was tuned to respond to 

 the waves given out by the primary. The current induced in 

 the secondary coil was passed round a light drum fastened to a 

 wire tuned to 400 vibrations per second. The drum was placed 

 in a strong magnetic field, and the electrical oscillations caused 

 mechanical vibrations of the drum. On to the drum was 

 attached one carbon of a microphone, and the induced oscilla- 

 tions were thereby considerably magnified in the microphone 

 circuit. This circuiL was also arranged in the same way as the 

 former, and by means of another microphone the vibrations 

 were transferred to another circuit where their intensity was 

 sufficient to actuate the diaphragm of an ordinary telephone 

 receiver to such an extent as to render the sound perfectly 

 audible. Mr. Watson described some experiments which he 

 had shown to illustrate syntony, both by obtaining galvanometer 

 deflections and sparks in the secondary circuit. Dr. Lehfeldt 

 asked how the circuit was tuned when it contained both a 

 variable capacity and a variable self-induction. Mr. Shaw said- 

 that the values of the capacity and self-induction were connected, 

 with the vibration frequency by a formula given by Dr. Lodge. 

 Starting with a known capacity, the necessary self-inductioft 

 was calculated and small alterations produced by means of an 

 iron core. — Mr. Shaw then read a paper on an electrical micro- 

 meter. In this paper the motion of the centre of a telephone 

 diaphragm was measured by means of a system of levers and a 

 spherometer screw. The screw, which had a pitch of o*S. 

 mm, and a head divided into 500 parts, pressed against 

 the long arm of an aluminium lever. The short arm 

 of this lever pressed against the long arm of another, 

 and so on through three levers. In this way any 

 motion of the spherometer screw was transmitted to a fine 

 platino-iridium point close to a small platino-iridium disc fas- 

 tened to the centre of the telephone diaphragm. Since the 

 head of the spherometer could be accurately read to 01 of a 

 division by means of a telescope, and since the system of levers 

 minified any motion a hundred fold, it follows that an accurately 

 observable twist of the spherometer head corresponds to a 

 movement of a millionth of a millimetre or i fifx of the fine 

 point. To test the action of the levers, the point was removed 

 and a convex lens substituted. This lens formed one of a 

 system by means of which Newton's rings were produced an'd 



