January. 1912. 



KXO\VLi:i)r,I- 



41 



anti boil at constant temperatures. Mr. Honsfield described 

 a temperature rej^ulator for use in an air bath. It consists of 

 a larKe bulb of tjlass containinK hydrogen. When this hydrogen 

 is raised in temperature it expands and increases the pressure 

 on a column of mercury in a barometer tube. When this 

 occurs an electric contact is broken which switches out the 

 electric heater. The mercury does not get attacked, because 

 the circuit is broken in an atmosphere of hydrogen. 



It is not easy to obtain a satisfactory method of maintaining 

 ' 'instant low temperatures over a long period of time. There 

 .ire a limited number of substances which can be used to 

 maintain constaut low temperatures, e.g., boiling sulphur 

 dioxide ( — 10°C), boiling liquid amnionia ( — J3 C), boiling 

 sulphuretted hydrogen ( — 61 ''O. boiling nitrous oxide ( — 83° C), 

 and boiling oxygen (185° CI; also melting ether, melting 

 nitrous oxide, and various " freezing mixtures," such as 

 solid carbon dioxide and ether. But in all these cases 

 a considerable quantity of the pure liquid is required, and the 

 li(|uefaction is a troublesome process. F"urther, if these liquids 

 are contained in a Dewar vessel, they supercool themselves 

 unless evaporated by an electric heating arrangement. 



The writer has recently been employing an arrangement for 

 maintaining temperatures constant over a range of temperatures 

 between +80 and — 150°C, but has not yet published the 

 method, as the details are hardly yet worked out. The general 

 principle is that the thermometer, on rise of temperature of 

 the bath liquid, makes an electric contact which switches in a 

 heating coil situated in a closed bulb containing the bath 

 li<iuid U'.g., petrol I ; this bulb communicates with a spiral 

 containing the same liquid immersed in a refrigerating agent ; 

 on heating the petrol in the top bulb, the pressure rises there 

 and forces cold liijuid from the spiral into the Dewar vessel 

 which contains the bath liquid. The electric contact, owing 

 to the fall in temperature, then breaks, and the liquid is sucked 

 b.ick into the spir.al and recooled. 



THE \\:.\l< 1911.— It would not be possible to review the 

 many advances made in the physical sciences during the year 

 1911 in the space of a few lines. One might direct attention, 

 though, to the main regions of activity. There are usually 

 one or two problems upon which the mind of man is concen- 

 trating its attack ; other points in the line of resistance of the 

 enemy remain in a more or less quiescent state. In radio- 

 activity. Professor Rutherford and his collaborators have, by 

 means of the beautiful scintillation method, investigated the 

 scattering of the rays by atoms of various substances and 

 have obtained v.iluable evidence on which to gain an idea of 

 the structure of the atom. Professor Sir J. J. Thomson has 

 concentrated his attention on the rays of positive electricity 

 which stream back through a hole in the cathode of a tube in 

 which a high vacuum is maintained. Others have investigated 

 the positive rays emitted by incandescent solids and analysed 

 the intricate actions which occur with some success. 

 Secondary rays emitted from materials bombarded by X rays 

 or corpuscular radiations have proved to be a problem of 

 great interest and about which considerable controversy has 

 been raised. Barkla and Bragg being the champions of the 

 two views as to the nature of X rays. Then again there are 

 the intensely interesting results of Professor Strutt, who has 

 obtained a chemically active modification of nitrogen by means 

 of an electric discharge, and has explained en route the 

 peculiar glow effect obtained in certain circumstances with 

 such discharges. Pnjfessor Woods' researches on the 

 fluorescence from certain vapours lead to an idea of the 

 vibrations and groupings of the electrons within the atom. 



Professor Callendar has pointed out how the old idea of 

 caloric may be of use in the study of thermodynamics, while 

 the mechanism of the osmotic pressure of liquids is beginning 

 to reveal itself. The motion of liquids in pipes and of solids 

 through li(|uids has been submitted to careful experiment 

 with useful results; while finally the theory of radiation and 

 .also of electric conduction and o^ther fundamental physical 

 properties has been advanced by means of what is known as 

 the relativity principle, to which it will be well to devote a 

 little space in the notes of the month of February or March. 



ZOOLOGY. 



By Pkoikssok J. Arthur Thomson, M.A. 



LARGE CUTTLEFISH.— It is always satisfactory to have 

 precise figures in regard to big animals, andno fault can be found 

 with the precision with which Mr. S. S. Berry has recorded 

 the dimensions of a huge cuttlefish from Monterey Bay. Its 

 total length was 124,t millimetres, that is rather over four feet ; 

 its length of body was 1180 millimetres. Its name is 

 Dosidiciis giiitis (d' Orbigny) Pfefl'er, and it is remarkable, 

 in addition to its size, for some peculiar features in the 

 suckers of the tentacles. The fine specimen is preserved in 

 the University of California. 



SELF- ADVERTISING ANIMALS.— Some animals walk 

 delicately, some lie low, some fade into their surroundings, 

 some put on disguise. On another tack, however, are those 

 that are noisy and fussy, conspicuous and bold,— the self- 

 advertisers. The theory is that those in the second set can 

 afford to call attention to themselves, being unpalatable or in 

 some other way safe. Mr. Pocock, of the Zoiilogical Society's 

 Gardens, has been recently applying this theory to various 

 mammals, both at home and abroad. 



Taking the common shrew, for instance, he points out that 

 it is fearless and careless, and that it makes a fretiuent 

 -squeaking as it hunts. It can afford to be a self -advertising 

 animal because of its strong musky scent, which makes it 

 unpalatable. A cat will never eat a shrew. Similarly, the 

 large Indian musk-shrew {Crocidiira coenilea) is con- 

 spicuous even at dusk, fearless in its habits, and goes about 

 making a peculiar noise like the jingling of money. But it is 

 safe in its unpleasant musky odour. 



The common hedgehog is comparatively easy to see at 

 night ; it is easy to catch, because it stops to roll itself up ; it 

 rustles among the herbage and "' sniffs furiously " as it goes ; 

 it is at no pains to keep quiet. Nor need it. for although .some 

 enemies sometimes eat it, it is usually very safe, partly in its 

 spines, and partly because it can give rise to a most horrible 

 stench. The porcupine is another good instance of a self- 

 advertiser, and so is the crab-eating nmngoose (Mun^os 

 caiicrivora). 



HOW MUCH DOES A MOUSE SEE ?— To look at .i 

 mouse one would think that sight counted for a great deal in 

 its life, but Mr. K. T. Waugh's experiments go to show that 

 this is only true within certain limits. Mice are good at 

 distinguishing different degrees of illumination and different 

 colours (preferring red and yellow to blue and green), and 

 they are quick to detect movements, but they have very little 

 sense of form and very Httle binocular vision. Microscopic 

 study shows that the retina has no " rods " and no " fovea." 



BRITISH FOSSIL SHREWS.— The remains of shrews 

 found in the Norfolk "Forest Bed" and other British 

 Pleistocene deposits have been hitherto referred to one or 

 other of the three species at present inhabiting the country, 

 namely Sorex araneus (or vulgaris), Sorex iiiinntiis, and 

 Neomys (or Crossopus) fodiens. But a careful inquiry 

 recently made by Mr. Martin A. C. Hinton shows that it is not 

 until we reach the latest Pleistocene deposits that we meet 

 with remains of species apparently indistinguishable from the 

 living British forms. According to Hinton we must recognise 

 at least three extinct species of Sorex and two of Neomys. 

 He regards Sorex as standing in most respects on a slightly 

 lower plane than Neomys. It retains one more premolar 

 above; in the large lower incisor three or four denticles 

 (primitively present upon the crowns of mannnaUan incisors) 

 persist until an advanced stage of wear has been reached ; the 

 condyle of the lower jaw and its articulation are less highly 

 modified. "In the small size of most of the species, their 

 external characters, and the form of the skull and humerus we see 

 the effects of an adaptation to life underground." The water- 

 shrew ^Neomys) has gone a little further and in a different 

 direction, in adaptation to a<iuatic life, which has to some extent 

 influenced its external characters. "A premolar has been lost 

 above ; the large lower incisor has been simplified— only one 



