January 9, 1902] 



NATURE 



239 



farther seaward. Trinidad has more continental features than 

 the other islands. Its surface-topography has been found to 

 owe its origin to the erosion features of the Miocene- Pliocene 

 period, which have been covered by only thin mantles as in 

 Barbados, so that its life-history falls into harmony with that of 

 the other islands. In its older beds it has the deep oceanic 

 oozes as in Barbados. No volcanic phenomena have been added 

 to the features of these islands. 



Royal Microscopical Society, Decemoer i8, 1901. — ■ 

 Mr. William Carrulhers, F.R.S., president, in the chair. — Messrs. 

 K. and \. Beck exhibited a new micrometer microscope, the 

 body of which was made to traverse across a long stage by 

 means of a fine screw, the milled head of which was divided so as 

 to indicate a movement of i/loo millimetre. The body could 

 also be placed in a horizontal position, when it could be used as 

 a telescope to measure distant objects. — Mr. F. W. Watson 

 Baker exhibited a number of microscopic specimens illustrating 

 the development and structure of eyes. They were shown 

 under twenty microscopes and were the most perfect sections 

 which could be obtained from the best preparers in this country 

 and abroad. — Mr. Nelson sent three notes which in his absence 

 were read by the secretary. The first was a description of 

 Holtzapffel's microscope. The date of it is 1830 and in it are 

 found four original devices,' (i) the clamp foot for clamping the 

 instrument to the edge of a table, predating a similar device of 

 Varley's in 1831 ; (2) the back of the mirror is flat polished 

 brass so that monochromatic light may be reflected by it ; (3) 

 the stage is focussed by an excentric which differs from 

 and predates the somewhat analogous devices of Pacini and 

 Plossl ; (4) the movement of the lens holder by means 

 of a steel tape and pinion. The second note was a 

 description of the first English achromatic objective, made by 

 W. Tulley. It was a triplet and was made at the suggestion of 

 Dr. C. R. Goring, who paid 90/. for it. The focus of the 

 combination is 0'933 inch, initial magnifying power 1072, N. A. 

 •259, and the O.I. the large amount of 24-2. Mr. Nelson then 

 described the Chevalier- Euler achromatic objectives of 1823-24 

 and 1S24-25. These were doublets, and in 1827 Mr. J. J. 

 Lister put one of the Chevalier doublets as a front and a TuUey's 

 triplet as a back lens. The focus of the combination was 0*52 

 inch and it was the finest microscopic objective that had up to 

 that time been produced, and was, strictly speaking, the first really 

 successful scientific microscopic objective. Lister's labours in 

 perfecting objectives and the great use they had been to the 

 leading opticians of the day were referred to. The third note 

 was on a useful caliper gauge. It can be purchased at any 

 watchmaker's tool shop for three or four shillings. It is 

 convenient for measuring the thickness of cover glasses, and 

 for low-power work the scale may be placed on the 

 stage of a microscope and the constant of an eye-piece 

 micrometer found by comparison with the mm. divisions. — 

 The president gave an account of some investigations which he 

 had made in reference to a disease that had caused great 

 mischief in the cherry orchards in Kent. About fourteen months 

 ago, when his attention was first directed to it, the disease was 

 prevalent over a considerable area, a noticeable feature in con- 

 nection with it being the persistence in the autumn of the dead 

 leaves on the branches, instead of their falling off, as they 

 would if the trees were healthy. The leaves of affected trees 

 were pervaded by the mycelium of a fungus which destroyed 

 them, and as the food of the tree was prepared by the leaves, 

 the growth of the tree would, as a consequence, be arrested. The 

 results of experiments in the cultivation of the fungus showed it 

 to be one which belonged to the genus Gnomonia. Many of 

 the fungi in this class passed through various stages in their life- 

 history, for example, the mildew on wheat, which was first deve- 

 loped on the berberry and then spread to the wheat, appearing 

 first as rust and afterwards as mildew from the same mycelium. 

 The president referred to the absence in this country of any 

 authority competent to investigate cases such as this ; on the 

 continent, however, the Governments had taken up the matter, 

 and the experts who had inquired into it had found that to 

 check the spread of the disease it was necessary to collect all the 

 dead leaves and burn them. The president had consequently 

 urged upon the fruit growers the necessity of following this 

 recommendation, but had only been able to persuade two 

 growers to do so ; both of these, however, had found it to be 

 thoroughly effective. Prof. .A. W. Bennett in his remarks 

 enlarged upon the absence in this country of investigations into 



NO. 1680, VOL. 65] 



such matters by State-paid establishments, and described what 

 was being done in the United States, where every State had its 

 own experimental station. 



Paris. 



Acadamy of Sciences, December 30, 1901. — M. P'ouque 

 in the chair. — M. .Albert Gaudry was elected vice-president for 

 the year 1902. — On double fertilisation in the Solanacea; and 

 Gentianacete, by M. L. Guignard. \s,l\\iy oi Niiotiana tahaaim 

 and Datura loevis in the Solanacea; and of Geiiliana ciliata 

 shows that double fertilisation is effected in both of these orders 

 in essentially the same manner as in other cases which have been 

 observed. — On a series of factorials, by M. Niels Xielson. — On 

 linear differential equations which are of the same species, by 

 M. Alfred Lcewy. — Some new theorems on entire functions, by 

 M. Ernst Lindelof. — On integral invariants and differential 

 parameters, by M. Alf. Guldberg. — Internal tensions produced 

 b}' two equal directly opposed forces acting on an indefinite 

 solid, by M. Mesnager. — The critical constants and molecular 

 complexity of some hydrocarbons, by MM. Ph. .A.. Tjuye and 

 Ed. Mallet. The critical pressures and temperatures ate given 

 for durene, naphthalene, diphenylmethane and diphenyl. From 

 these are calculated the critical coefficients, the constants a .and 

 b in Van der Waals' formula and the ratios of the real critical 

 density to the theoretical. The conclusion is drawn that none 

 of the hydrocarbons studied are associated at the critical point. — 

 The extension of Kirchhoft's laws, by M. E. Carvallo. The 

 results of this investigation are expressed as follows : The flux 

 of the total current through the whole of a closed surface is 

 zero, and the total electromotive force which rules in a closed 

 circuit is zero. — On a new reaction between electrostatic tubes 

 and insulators, by M. W. de Nicolaicve. — The action of high- 

 frequency currents upon animals, by MM. H. Bordier and 

 Lecomte. It has been shown that high-frequency currents can 

 be applied directly to man without any sensation being 

 produced, in spite of the large amount of energy which 

 can be thus transmitted. It has been suggested as an 

 explanation of the absence of sensation that the currents 

 pass over the surface of the body without penetrating it. 

 The experiments of the author negative this view, as such 

 currents were found to be fatal to the rabbit, guinea-pig and 

 rat. — Remarks on the preceding communication, by M. 

 d'Arsonval. The facts described by MM. Bordier and Lecomte 

 are in full accord with pievious observations of the author. 

 Stress is laid upon the conditions which must be observed in 

 studying high-frequency currents. It is necessary to avoid all 

 action on the sensibility, muscular contraction, and all abnormal 

 elevation of temperature. — On the existence of rays capable of 

 reflection in the radiation emitted by a mixture of the chlorides 

 of radium and barium, by M. Th. Tommasina. — On the electro- 

 capillary maxima of some organic compounds, by M. Gouy. — 

 The heat of formation of the hydrate of chlorine, by M. de 

 Forcrand. The number deduced from the dissociation curves 

 of Isambert, Roozeboom and Le Chatelier is iS'l6 calories; 

 the value obtained from direct experiment is lS'57. — On the 

 determining causes of the formation of the visual organs, by M. 

 Antoine Pizon. The phenomenon of vision is regarded simply 

 as a consequence of the accumulation of pigmentary granules at 

 certain points of the body, and of the absorbing power of these 

 granules for light rays. These views are regarded as affording 

 an explanation of the occurrence of the eyes in the regions of 

 greatest illumination, the position of the cephalic eyes, the ex- 

 traordinary number of eyes in certain annelids, the more or less 

 complete disappearance of the eyes in species inhabiting caves 

 and in internal parasites. —The leaf trace in ferns, by MM. C. E. 

 Bertrand and F. Cornaille. — On the eclogites of the Aiguilles 

 Rouges, by M. Etienne Joukowsky. — On ergot of rye, by M. 

 Marcel Guedras. The therapeutic action of this drug is due 

 to sphacelinic acid and to cornutine. These active principles 

 cannot be separated practically, since they have nearly the same 

 solubility. 



New South W.\les. 



Linnean Society, November 27, 1901. — Prof. J. T. Wilson 

 in the chair. — The following papers were read : — Descriptions 

 of new genera and species of Australian Lepidoptera, by Mr. 

 Oswald 15. Lower. Sixty-seven species referable to six families, 

 namely, Arctiad;e 2, Noctuidse 39, Thyridida: I, Pyralid;\; 23, 

 Tortricidie i, Plutellida; i. — The deterioration of raw and refined 

 sugar crystals in bulk, by Mr. R. Greig Smith. The deterioration 

 of bulk crystals is in many cases caused by Bac. levaniformain. 



