460 



NA TURE 



[August 30, 1906 



(21 CHCI3 to the inner surface leaves the current un- 

 affected. 



(3) CHCIj to a combination of (outer-inner) surfaces, 

 connected with another spot on the outer surface, diminishes 

 the current. 



(4) The electrical resistance of the skin is diminished by 

 about 24 per cent, of its value by CHCl,. 



Certain conclusions can be deduced from these observ- 

 ations : — 



(a) The apparatus furnishing the current is located at 

 the outer surface. 



(b) A diagram of an electrical apparatus which would 

 give similar results to those observed on the skin shows 

 that the latter nxist consist of structures resembling 

 galvanic cells, the positive elements of which lie towards 

 the outer surface, and are insulated from each other, the 

 negative elements towards the inner surface, and connected 

 together. If it is assumed that the current in the skin is 

 diie to the movement of ions, it appears from the present 

 experiments (and also from those in part i.) that there 

 must be some semi-permeable apparatus in both skin and 

 -nerve, and that choloroform renders this apparatus com- 

 pletely permeable, so making the whole tissue iso-electric. 

 The diminution of resistance can be accounted for by this 

 action, which is equivalent to a diminution of viscosity. 



If this interpretation of the results is correct, it furnishes 

 an actual demonstration of the existence of some form of 

 semi-permeable apparatus in the tissues, and suggests that 

 a similar mechanism may play a larger part in vital pheno- 

 mena than had previously been supposed. 

 Paris. 



Academy of Sciences, August 13. — M. Bouquet de la 

 Grye in the chair. — Irrigation and the permeability of 

 soils : A. Mijntz and L. Faure. The authors discuss the 

 value of the application of irrigation to parts of France, 

 and argue that irrigation works must prove unremunerative 

 in private hands, and should be undertaken by the State. 

 Proper attention does not appear to have been paid in the 

 past to the different requirements of different classes of 

 soil for water. The nature of the soil is not a sufficient 

 guide in this matter, apparently similar soils having been 

 found to require very different amounts of water. A de- 

 scription is given of a simple instrument for making this 

 determination. — The two specific heats of a slightly de- 

 formed elastic medium ; the fundamental formulae : P. 

 Duhem. — The preparation of pure barium starting from 

 its suboxide : M. Guntz. Equivalent portions of mag- 

 nesium and baryta, heated in a vacuous porcelain tube 

 containing a water-cooled steel tube, gave a deposit on 

 the cold tube of one-half the magnesium employed, together 

 with traces of barium. The residue in the boat possessed 

 properties corresponding to "an oxide Ba,0. If the mag- 

 nesium is replaced in this reaction by aluminium, crystal- 

 lised barium deposits on the cold tube. This was found 

 to contain 98-8 per cent, of barium, and on a second dis- 

 tillation in a vacuum gave pure barium. Strontium can 

 be obtained in the same way. — The aromatic azocyan- 

 amides : P. Pierron. — K property of diastase : J. Duclaux. 

 The application of recent studies on colloids to diastase. 

 The author holds that the quantity of active material in 

 diastase, by reason of which it exerts its diastatic func- 

 tions, need, in a set of experiments, bear no constant and 

 necessary relation to the quantity of crude diastase taken, 

 and that different experiments, even simply made at 

 different dilutions, are not comparable among themselves. 

 — The copper-steel alloys : Pierre Breuil. Copper in- 

 creases the tenacity and reduces the ductility of steels, but 

 the results obtained with a given alloy depend very largely 

 upon the treatment the metal has received. — The cultiva- 

 tion of micro-organisms in chemically defined media : 

 J. Galimard, L. Lacomme, and A. Morel. 



August 20. — M. Bouquet de la Grye in the chair. — The 

 progress of a fruit-attacking insect, Ceratitis capitata, in 

 the neighbourhood of Paris : Alfred Giard, Six years ago 

 the author pointed out the presence of this destructive 

 exotic in the neighbourhood of Paris. At that time there 

 were only a few apricot trees attacked, and it should have 

 been easy to prevent its acclimatisation. The author's 

 suggestions made at that time were, however, disregarded, 

 and at the present time damage is being done to peach 



NO. 1922, VOL. 74] 



trees in various localities round Paris, damage which may, 

 given a few dry seasons, become as disastrous as at the 

 Cape of Good Hope, unless prompt measures are taken. 

 — The Valparaiso earthquake (August 16, 1906), registered 

 at Pans : G. Bigourdan. — Observations of the Finlay 

 comet made with the large equatorial of the Bordeaux 

 Observatory : E. Esclanson. — Definitive orbit of the 

 comet 1905a : M. Giacobini. — The boiling points of some 

 secondary and tertiary alcohols : G. D. Hinrichs. Refer- 

 ring to a recent note by M. Louis Henry on this subject, 

 the author points out that the relationships between the 

 boiling points of the secondary and tertiary alcohols need 

 not be regarded as unusual, since they can be deduced, at 

 least qualitatively, from a consideration of the moments 

 of inertia of the molecules. — Researches on the relations 

 between functional groupings in distant positions. Deca- 

 methylene-imine : E. E. Blaise and L. Houillon. — The 

 influence of some mineral compounds on the liquefaction 

 of starch : J. Wolff and A. Fernbach. — Cultures of 

 Protozoa and variations of living material : J. Kunstler 

 and Ch. Gineste. 



New South W.4les. 

 Royal ^Society. July 4.— Prof. T. P. Anderson Stuart, 

 president, in the chair. — The testing of building materials 

 on abrasion by i^ie sand-blast apparatus : H. Burchartz. 

 The paper described a method of testing building material 

 by means of a sand-blast apparatus. The sand-blast 

 apparatus is used on cubes of the material, exposing an 

 area of 4-34 square inches for two minutes, and the loss 

 of weight, and the appearance of the area eroded by the 

 sand, give accurate data in regard to the durability of the 

 material. The author compared the results of testing a 

 great variety of materials by means of the sand blast with 

 those subjected to the grinding process proposed by 

 Bauschwiges, and showed the superiority of the sand blast 

 over all other tests for abrasion. 



CONTENTS. p.\GE 



The Late Duke of Argyll 437 



Chemistry and the Detection of Crime. By C. S. . 440 



Nervous Disease 440 



Our Book Shelf: — 



Mathey : " Traite d'E.-cploitation commerciale des 



Bois" 441 



"Illustrations of British Blood-sucking Flies." — 



W. F. K 441 



Villiger : " Gehirn und Riickenmark. Leitfaden fiir 

 das Studium der Morphologic und des Faser- 



verlaufs " 442 



Erdroann and Kcithner : " Naturknnstanten in alpha- 



betischer Anordnung." — ^J. A. H 442 



Letters to the Editor : - 



Thermodynamic Reasoning. — Prof. Henry E. Arm- 

 strong, F.R. S. ; W. C. D. Whetham, F.R.S. 443 



The Iron Arc— Prof. W. G. Cady 443 



Volcanoes and Radio activity. — Dr. T. J. J. See . . 444 

 The Radio-activity of the Chemical Elements. — C. W. 



Raffety . . 444 



The Oxidation of Atmospheric Nitrogen in the 

 Electric Arc. {Illustrated.) By Dr. F. Mollwo 



Parkin 444 



The Electrical Signs of Life and their Abolition by 

 Chloroform. {/lliistiated.) By Dr. Augustus D. 



Waller, F.R.S 447 



Meteorological Kites in India 44S 



Notes . . - . 44S 



Our Astronomical Column : — 



Astronomical Occurrences in September 452 



Discovery of a New Comet (i9o6«) 452 



Finlay's Comet (1906?/) 453 



Greenwich Sun-spot Numbers 455 



The Origin of the Zodiacal Light 453 



A Modified Form of Solar Eye-piece 453 



Physics at the British Association. By A. W. P. . 453 



Anthropology at the British Association 456 



M. Lippmann's Method of Photography in Colour 459 



University and Educational Intelligence 459 



Societies and Academies 459 



