April 



1908] 



.\'.^ TURE 



5 89 



lime the calorific value of the gas would remain constant, 

 so that th(^ effect of changing the strength of mixture or 

 of scavenging by running without load could be vury 

 accurately determined. When allowance is made for the 

 gas discharged unburnt, the efficiency is not much affected 

 by scavenging provided the strength of mixture is kept 

 the same, which implies an increase of about 15 per cent, 

 in the gas-charge, with, of course, a corresponding increase 

 of mean pressure, .^t the same meeting Mr. James 

 .Atkinson read a paper on the governing and regularity 

 of gas-engines, in which the various methods of governing 

 employed were critically discussed. 



The report of the Observatory Committee of the Royal 

 Cornwall Polytechnic Society for the year 1907 has been 

 received. The Falmouth Observatory is one of the 

 important meteorological establishments subsidised by the 

 London Meteorological Committee for the tabulation of 

 automatic records ; it has a complete magnetic equipment, 

 and during the year in question received material assist- 

 ance from the Royal .Society towards the maintenance of 

 this branch of its useful work. The observations fairly 

 represent the conditions in the west of England ; the mean 

 temperature of 1907 was o°-4 below, and the rainfall 2-78 

 inches above, the mean. During a brilliant display of 

 aurora, on February 9, the magnetographs showed that 

 a storm of great intensity was in progress. 



The Stonyhurst College Observatory (Lancashire), which 

 has likewise sent us a copy of the results for 1907, also 

 receives some allowance from the Meteorological Office. 

 Its records (together with those of the Liverpool Observa- 

 tory) represent the meteorological conditions in the north- 

 west district of England, and it possesses a valuable series 

 of observations extending over sixty years. The rainfall 

 of the year was 3 inches above, and the temperature o°-6 

 below-, the average. Magnetic observations are carefully 

 recorded, but the staff is too limited to undertake hourly 

 tabulations from the curves. Some ig8 drawings of sun- 

 spots and faculae were made, and Father Sidgreaves re- 

 marks on an unexpected revival of solar activity and 

 magnetic diturbance. 



The Royal Geographical Society has published a 

 " Bibliography of Topographical and Geological Works 

 on the Phlegraean Fields," by Mr. R. T. Giinther, con- 

 taining about 2200 titles of books, papers in scientific and 

 other periodicals, maps, and drawings, relating to the city 

 of Naples and the country to the west of it, together with 

 the volcanic islands in the vicinity. The catalogue is 

 specifically restricted to the geomorphology, topography, 

 and physical features of the region, and is arranged 

 as a subject catalogue, the entries being grouped in 

 topographical sections or sections devoted to special sub- 

 jects, and printed in each group consecutively in order 

 of date of publication. When supplemented, as in this 

 case, by an index of authors and subjects, no more con- 

 venient arrangement could be devised. The catalogue will 

 be of great service to students of volcanic and kindred 

 phenomena, and to others interested in the region dealt 

 with, but the reference to geology in the title might well 

 have been omitted, for the list is by no means complete in 

 this department ; we notice the inclusion of papers which 

 have no real bearing on the subjects to which the biblio- 

 graphy is restricted, and the omission of others which 

 should have been included. 



The Miirch number of the Psychological Review con- 

 tains the second of two interesting articles, by Dr. Boris 

 Sidis, setting forth a new explanation of hallucinations. 

 NO. 2008, VOL. 77] 



h is based upon a novel theory of perception, the exposi- 

 tion of which was contained in the former article. The 

 perception of an object involves, as is well known, a 

 reference to other sense qualities of the object than those 

 immediately presented. Thus we may " see," not only 

 the transparency, smoothness, and whiteness of a lump of 

 ice, but also its coldness and weight. Former doctrines 

 of perception have regarded the latter factors of the per- 

 ceptual complex as" images ; in opposition to this view' Dr. 

 Sidis maintains that, like the former, they are sensational. 

 He distinguishes them from the sensational elements the 

 material causes of which actually affect the sense organs, 

 by calling the latter " primary " and the former 

 " secondary sensory elements." In normal perception we 

 have a group containing elements of both types organised 

 round a nucleus of primary elements, but under abnormal 

 conditions it may happen that the primary sensory elements 

 become subconscious or fall entirely out of the patient's 

 consciousness, leaving a group of secondary sensory 

 elements standing as an independent synthetised compound. 

 .Such a dissociated group of secondary sensory elements 

 constitutes an hallucination. 



Dr M. JIarage described before the Paris Academv of 

 Sciences a method invented by him of photographing the 

 vibrations of a thin india-rubber membrane when acted on 

 by the tones of the human voice. A small mirror is 

 attached to the membrane, and a beam of light is reflected 

 from it upon a band of sensitised paper slowlv moved by 

 a small electromotor. After receiving the impression the 

 photographic paper is drawn by the motor through two 

 developing baths, and finally into a fixing bath. There is 

 nothing strikingly novel in the method, and the examples 

 of the tracings given in the paper published in the Compics 

 rendus of the academy do not seem to be clear or to give 

 much information. 



Mr. J. W. GiLT.w, of Delft, Holland, has sent us a 

 descriptive catalogue of apparatus for demonstrating the 

 action of light on selenium. The selenium cells listed are 

 of the Shelford Bidwell type, their resistance in the dark 

 ranging from 25,000 ohms to 500,000 ohms. Low resist- 

 ance and high sensitiveness, it is noted, do not go together. 

 These cells have been manufactured bv Mr. Giltay ever 

 since 1881, and among those to whom they have been 

 supplied is Dr. Korn, who uses them in his well-known 

 process of telegraphic photography. Their capabilities in 

 this direction are demonstrated by a reproduction of an 

 e.xcellent portrait of Dr. Korn, which was transmitted 

 electrically. Among other apparatus described is a minia- 

 ture photophone. Words spoken into the mouth-piece of 

 the transmitter act upon an acetylene manometric flame, 

 which illuminates a selenium cell placed near it ; the cell 

 is connected in circuit with a battery and a telephone 

 receiver in a distant room, and the speaker's voice is heard 

 at the telephone. Several modifications of this apparatus 

 are described. A compact battery of forty-nine cells, pro- 

 viding the high electromotive force requisite for experi- 

 ments with selenium, is supplied at a moderate price. 



I.c Radium for March contains an account of the work 

 done recently by M. A. Dufour on the effect of pressure 

 on the wave-lengths of the absorption lines of nitrogen 

 peroxide and bromine. The observations made hitherto 

 on the effect of pressure on emission spectra have led to 

 the conclusion that the lines of bands were unaffected. 

 M. Dufour finds, on the contrary, that certain lines of 

 the absorption spectra of the two vapours mentioned are 

 influenced by pressures up to about 20 atmospheres. The 

 whole of the lines of the absorption bands are broadened 



