May 3, 1894] 



NA TURE 



any good indicator it probably answers the purpose. The 

 coil test is mentioned, but it is very properly pointed out 

 that the appearance of the luminosity in an exhausted 

 bulb is not "under all conditions an indication of the 

 state of the vacuum." 



A good chapter is devoted to the testing of voltage and 

 candle-power. The methods of using the photometer 

 are fully described; the "Harcourt" pentane lamp is 

 said to make the most trustworthy standard, but for 

 regular factory use an argand burner with a Methven 

 screen is recommended. This is occasionally tested with 

 the pentane lamp. Then follows a full description, with 

 drawings, of Evershed's wattmeter ; and the chapter 

 closes with a method of finding the mean horizontal 

 candle-power of lamps with either tlat or cylindrical 

 filaments. 



A short description is given of the method of capping 

 the finished lamp. The author finds that the addition of 

 a small percentage of de.\trine to the plaster of paris 

 makes a very hard cement, and he warns makers against 

 using an acid flu.\ for soldering the wires and connections. 

 Nothing but rosin should ever be used. 



In the chapter on efficiency and duration, allusion is 

 made to the expression "watts per candle-power," in- 

 stead of the more correct term " candle-power per watt," 

 pointing out that it is more easy to grasp the meaning of 

 1 certain number of watts than of a particular fraction of 

 1 candle-power. In connection with duration tests, it is 

 kery justly said that "life tests pure and simple" are 

 worthless unless the actual candle-power of the lamp at 

 different periods of its life are given. 



In the life of a lamp the advantage of the hard coating 

 Df deposited carbon shows itself This hard carbon, 

 :ombined with a good vacuum, greatly retards the falling 

 off of candle-power due to the blackening of the bulb. It 

 Is explained that the disintegration of the carbon acts in 

 three ways. Firstly, by coating the glass with deposited 

 :arbon and thus obscuring the light ; secondly, by alter- 

 ing the surface of the filament and increasing its 

 emissivity so that it is at a lower temperature ; and 

 thirdly, by increasing its resistance so that it takes 

 less current. The data of experimental tests on 

 several lamps for efficiency and duration close the 

 chapter. 



The last chapter takes up the relation between 

 light and power in incandescent lamps, and details are 

 given of the recent tests made under the direction of 



rof Ayrton at the City and Guilds of London Institute, 

 ith drawings of curve diagrams showing the candle- 

 ower and watts of lamps of various makes, up to 

 he breaking point. In conclusion it is said that the 

 Ideal lamp would be one in which the radiation is wholly 

 luminous, and that the carbon incandescent lamp falls 

 very short of this desirable consummation. Brief 

 -eference is made to the beautiful experment of Nicola 

 Tesla. 



On the whole, readers will find the book to be of very 

 :onsiderable interest, dealing as it does with an entirely 

 lew industry of very great elegance ; and the practical 

 knowledge diffused by its publication will certainly help 

 ;o advance the evolution of an efficient lamp which can 

 Je sold for a reasonable price, 

 vo. 1279, VOL. 50] 



ALGEUONICS. 

 Pain, Pleasure, and Aisthetics ; an Essay concerning 

 the Psychology of Pain and Pleasure, with special 

 refere7ice to /Esthetics. By Henry Rutgers Marshall, 

 M.A. (London : Macmillan, 1894.) 



ALGEDONICS is the term which Mr. Marshall 

 suggests for the science of pain and pleasure. In 

 his sixth chapter he gives the derivation of the term 

 thus : " 0X705-, [pleasure ; i)hovi], pain '' ; the discovery of 

 which, when he glanced over the pages of the completed 

 volume, must, we fear, have given him an algedonic 

 thrill. There is good stuff in the work, and the author 

 is evidently well up in the literature of his subject. 



In the first chapter, on the classification of pleasure 

 and pain, Mr. Marshall discusses the psychological 

 status of algedonic states. He argues, successfully we 

 think, against the view that pleasure and pain are 

 psychical elements sui generis with special nerves and 

 specialised cerebral centres ; and for the view that they 

 are due to algedonic tone associated with any or all of 

 the psychical elements. " Pleasures and pains," he says, 

 " may be differential qualities of all mental states of 

 such nature that one of them must, and either of them 

 may, under proper conditions, belong to any element of 

 consciousness." In his discussion, however, he does not 

 bring out the fact, which is readily explicable on his 

 view, that in popular speech we apply the term pain to 

 the somewhat heightened affections of common sensi- 

 bility, even when these affections are pleasurable. If, for 



j example, we lightly touch a slight bruise, we term the 

 sensation pain ; but such " pain " may be, if we can 



I trust our own experience, distinctly pleasurable. Since 

 the fibres by which impulses from the nerve endings of 



j common sensibility are transmitted, have special cortical 

 endings, and seem to run, in part at least, along different 



I tracts or in a different manner in the spinal cord, some 

 colour has been lent to the view, that there are special- 

 ised fibres and centres for pain. If, however, such 

 "pain" is merely the algedonic tone of common sen- 

 sibility (as hinted, but not in so many words, by Mr. 

 Marshall, on p. iS), these observations are quite in 

 accordance with the view which our author advocates. 

 .Mr. Marshall quotes Mr. Herbert Spencer s opinion that 

 " a relation proves itself to be itself a kind of feeling — 

 the momentary feeling accompanying the transition from 

 one conspicuous feeling to another." The word " feeling " 

 is here used in its most general sense as an affection of 

 consciousness. But Mr. Marshall appears to miss the 

 importance of the fact that such feelings of relation have 

 their algedonic tone no less than sense-impressions, a 

 realisation of which would, we think, have helped him in 

 his consideration of aesthetics. 



In accordance with the view adopted in chapter i., we 

 find that the emotions are regarded in the second chapter as 

 deriving their character from the algedonic tone of complex 

 co-ordinations of motor activity. Describing the psycho- 

 logical equivalents of these complex co-ordinations as, 

 in their sensation aspect, " instinct-feelings," he regards 

 them in their algedonic aspect as emotions. But here 

 again he is rightly anxious to lay stress upon the fact, 

 that the emotions, like pleasure and pain, are not some- 



