Oct. 12, 1883.] 



KNOWLEDGE ♦ 



223 



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AN ILLUSTRATED ^^ ^^ 



MAGAZINE OF SCIENCE^ 



fePl-AINLYVf ORDED -£XACTLYDESCRIB£D 



LONDON: FRIDAY, OCT. 12, 1883. 



Contents of No. 102. 



PiOB 



British Association Scraps 223 



A Naturalist's Year. Tha Shrews 



Die. By Grant Allen 224 



The j Chemistrv of Cookery. XX. 



By W. Matti'eu WUliams 226 



The Sim's Distance. By Professor 



R. S, Ball, LL.D 220 



Editorial Gossip 228 



Voices of the Suns. By Tcga 229 



PAGE 



"Weather Forecasts, and How to 

 Make Them : The Rain - Band 

 Spectroscope. [Illua.j By John 



Browning, F.R.A.S 229 



Ephemera, or Day Flies. (Illits.)... 230 

 The Face of the Sky. By F.R.A.S. 233 

 Correspondence : Pons'a Comet — 



Sir William Herschel, &c 333 



Our Chess Column 235 



BRITISH ASSOCIATION SCRAPS. 



Dr. Stone read a paper on the electrical resistance of 

 the human body. He began by observing that the appli- 

 cation of this powerful force to the organism in a scientific 

 manner -was still in embryo, and that the results had 

 hitherto fallen far below what might be expected. The 

 main difficulty in obtaining this resistance lay, first, in the 

 difficulty of making good contact through the skin of a 

 living man, and, secondly, in the rapid electrolysis which 

 takes place in the tissues when a current passes through 

 them. The resistance of the skin, he thouglit, had been 

 greatly overstated, and might easily be overcome by very 

 large electrodes saturated with a conducting solution. The 

 electrolysis was checked by alternating contacts and 

 momentary duration of tlie current. In this way he had 

 obtained very satisfactory results — among others, the in- 

 teresting physiological observation that a man of 5 ft. C in. 

 in height, another of G ft. 3 in., and the Hungarian giant, 

 who was 8 ft. high, nearly all gave from the wrist to the 

 ankle a resistance close upon a thousand Ohms, the larger 

 man being decidedly the better conductor. Tlic influence 

 of temperature and of disease was also adverted to, the 

 body apparently following the law of solid conductors, in- 

 creasing in riisistance with heat and becoming a far better 

 conductor when siiliering from paralysis than in the con- 

 dition of health. 



Dr. Stone also read a paper on some efiects of brain dis- 

 turbance on the handwriting. It was not surprising, he 

 said, that ailections of the cerebral hemispheres competent 

 to interfere with the complex co-ordination of speech should 

 also show their influence on the similar act of writing. 

 Essentially both functions were acquirements which by 

 practice had liccomo automatic, and were put forth involun- 

 tarily. He said, therefore, that as the defect known as 

 aphasia might occur in ditlcrent parts of the circuit, so 

 might grapiiic niodillcations. Three such cases he described, 

 one of wliich occurred to hiuLself personally. After sus- 

 tained mental elibrt, he fell down in a partial state of in- 

 sensibility. During three weeks delirium and delusions 



predominated over physical depression. These were liroken, 

 however, by lucid intervals. The leading feature of all his 

 aberrations seemed to have been reduplication. He doubled 

 the number of his sisters, his nurses, and his medical 

 attendants. When ho returned to himself and could trust 

 his memory and senses he found two things — first, what he 

 had been accustomed to call aphasia ; secondly, that he 

 could not write as he intended. The tendency to redupli- 

 cation, which was obvious in his delusions, was as clear as 

 need be in his writing, and the trick of including otiose 

 letters in familiar words lasted for some time. It was pro- 

 bably the trace either of mental stammering or of diplo- 

 graphia, depending upon want of synchronism between the 

 two hemispheres of tlie brain. That such a condition of 

 the ocular muscles occurred in drunkenness was well known. 



Mr. E. p. Culverwell read a paper on the probable 

 explanation of the effect of oil in calming wa'^es in a 

 storm. He said when the surface of the sea liad become 

 smooth after a storm it was very common for long rollers 

 to break on a sand-bar. If there were no wind and the 

 sea was glassy, these would not break until quite close to 

 the shore, even though the ordinary theory pointed to 

 their breaking earlier, unless there was a force directed 

 opposite to that of their motion. When exerted on the 

 waves, such a force might be supplied by the wind ; but if 

 it rose in any direction the waves broke much sooner. This 

 result was, therefore, due to some secondary effect produced 

 by the wind pressure, and not directly by the pressure 

 itself, and it was to the ripples produced on the surface, 

 which disturbed the wave motion, that the speedy breaking 

 was to be attributed. It was, however, a direct result of 

 the theory that the ripples depended on surface tension 

 for their propagation, and could not exist in large amount 

 on the oiled surface. It was also evident that the hold of 

 the wind on the wave was greatly decreased by the absence 

 of ripples, and thus the oil acted both to prevent the wind 

 having much ell'ect on the surface, and also to modify the 

 motion of the water in the wave. 



Professor Stokes read an important paper by Dr. 

 Huggins on coronal photography without an eclipse. In a 

 paper read before the Royal Society some time back, Dr. 

 Huggins had shown that it was possible by isolating, by 

 means of properly chosen absorbing media, the light of the 

 sun in the violet part of the spectrum to obtain plioto- 

 graphs of the sun surrounded by an appearance distinctly 

 coronal in its nature. These researches liave been con- 

 tinued, using a reflecting telescope by the late Jlr. Lassell, 

 and a film of silver chloride as the sensitive plate, on which 

 the photograph is taken. These plates are sensitive to tlie 

 violet light only, and therefore it was unnecessary to use 

 absorbing media, which had proved a source of difficulty, to 

 sift the light. Fifty photographs in all were taken and 

 examined afterwards by Mr. Wesley, who made drawings 

 of them for the paper. The details shown agree well with 

 the photographs of the corona made during tlio late solar 

 eclipse, the agreement being specially marked in two cases, 

 dated April 3 and June 5. The photographs have been 

 seen by the observers sent to Caroline Island to observe 

 the eclipse, and one of these writes that Dr. Huggins's 

 coronas are certainly genuine up to 8' from the sun's limb. 

 Dr. Ball, wlio was in the chair, examined some of the 

 plates, and spoke of the interest and importance of this 

 communication. 



