August 19, 1920] 



NATURE 



779 



that it can be) that in this field helium possesses 

 any advantage over the oils now used. 



It has been suggested by Elihu Thomson and 

 others that if divers were supplied with a mixture 

 of oxygen and helium, the rate of expulsion of 

 carbon dioxide from the lungs might be increased, 

 and the period of submergence as a consequence 

 be considerably lengthened. 



It is probable, however, that in the field of low- 

 temperature research helium will immediately find 

 its widest application. For this work helium is 

 unique in that, when liquefied and possibly solidi- 

 fied, it enables one to reach the lowest tempera- 

 tures attainable. Every effort should be exerted 

 towards the exploitation of its use in this 

 direction. 



One point that is important and should not be 

 overlooked is that the supplies of natural gas from 

 which helium can be extracted are being rapidly 

 used up. When our natural gas fields are depleted 

 it would appear that our main source of supply of 

 helium will have disappeared. Careful considera- 

 tion should, therefore, be given to the problem of 

 producing helium in large quantities while it is 

 still available, and of storing it up for future use. 

 As already stated, it may be that in the future it 

 will be of paramount importance to have even a 

 moderate supply of the gas available. 



A. Cryogenic Laboratory. 



To chemists and physicists especially, the dis- 

 < overy that helium can be produced in quantity at 

 a moderate cost opens up a vista in the realm of 

 low-temperature research of surpassing interest. 

 By means of liquid oxygen, the properties of sub- 

 stances can be studied down to a temperature of 

 - 182-5° C. Liquid nitrogen provides us with a 

 temperature of —193-5° C, and hydrogen, which 

 was originally liquefied in 1898 by Sir James 

 Dewar, enables us to reach — 2528° C. It is but 

 a few years since Onnes, after prolonged effort, 

 secured sufficient helium to enable him to liquefy 

 this gas, too. In a brilliantly conceived research 

 he succeeded in accomplishing this feat in 1908, 

 and in doing it reached a temperature within 

 approximately 1° or 2° C. of the absolute zero. 



The amount of liquid helium which Onnes ob- 

 lined in his investigation was small, but it 

 >ufficed to enable him to show that a number of 

 the elements possessed a remarkable "super-con- 

 ductivity " at this low temperature. Mercury in 

 particular, at the temperature of liquid helium, 

 possessed an electrical conductivity ten million 

 times greater than at ordinary room temperature, 

 and currents started by induction in a coil of lead 

 wire at the temperature of liquid helium main- 

 tained their intensity for more than an hour with 

 but little diminution in magnitude. 



The results obtained by Onnes, although limited 

 in number, are of great importance, for they show 

 that if liquid helium were rendered available in 

 quantity, fundamental information of the greatest 

 value on such problems as those connected with 

 electrical and thermal conduction, with specific and 

 XO. 2651, VOL. 105] 



atomic heats, with magnetism and the magnetic 

 properties of substances, with phosphorescence, 

 with the origin of radiation, and with atomic 

 structure, could be obtained. 



In spectroscopy supplies of liquid helium would 

 enable us to extend our knowledge of the fine 

 structure of spectral lines, and thereby enable us 

 to obtain clearer ideas regarding the electronic 

 orbits existing in the atoms of the simpler 

 elements. This would lead naturally to clearer 

 views on the subject of atomic structure generally. 



In other fields, too, important information could 

 be obtained by the use of temperatures between 

 that of liquid hydrogen and that of liquid helium. 

 What of radio-activity? Would this property be 

 lost by uranium, thorium, radium, and other 

 similar elements at temperatures attainable with 

 liquid helium ? Would all chemical action cease at 

 these temperatures? Would photo-chemical action 

 disappear completely? \\'ould photo-electric action 

 cease or be maintained at such low temperatures? 



In the fields of biological and botanical research, 

 information on problems pressing for solution 

 could be gained also. For example, would all life 

 in spores and bacteria be extinguished by subject- 

 ing them to temperatures in the neighbourhood of 

 absolute zero? 



The list of problems rendered capable of attack 

 by the use of liquid helium might be easily ex- 

 tended ; but those cited already will serve to show 

 that the field is large, and that it is well worth 

 while for us to make a special effort to secure 

 adequate financial support for the equipment and 

 maintenance of a cryogenic laboratory within 

 the Empire. 



It is probably beyond the ordinary resources of 

 any university to equip and maintain such a labo- 

 ratory ; but the project is one which merits 

 national, and probably Imperial, support. It 

 should appeal to private beneficence as well, for it 

 is a project deserving strong and sympathetic 

 help. 



A properly equipped cryogenic laboratory should 

 include : 



(i) A liquid-air plant of large capacity. 



(2) A liquid-hydrogen plant of moderate capacity. 



(3) A liquid-helium plant of small capacity. 



(4) Machine tools, cylinders, glass apparatus, 

 measuring instruments, etc. 



Such an equipment would probably cost more 

 than io,oooL 



For building purposes, probably an additional 

 10,000/. or 15,000/. would be required. 



The staff should include one or two skilled 

 glass-blowers, two or three mechanics and instru- 

 ment-makers, and two or three helpers for run- 

 ning the machinery. To provide this staff and 

 meet charges for light, heat, and power, probably 

 3000/. a year at least would be needed. 

 • For an administrative and technical staff, 

 probably 2500/. would be necessary. 



In addition to the above, special provision 

 would have to be made to secure an adequate 

 supplv of helium. If industrial uses can be found 

 for helium and a works were established in 



