July 28, 1898] 



NATURE 



I'i^'i- 



height and route of the balloon may be determined. He 

 also exhibited a very sensitive thermometer having a spiral 

 silver tube for its bulb soldered to a glass tube, both being 

 filled with the liquid toluene. — M. Teisserenc also showed 

 a very sensitive self-recording thermometer which is, at 

 the same time, almost insensible to shocks. — Mr. Rotch 

 read a paper on the use of kites, based on the experi- 

 ments carried on at Blue Hill Observatory. The Conference 

 recommended their use as being of great value to meteorology. 

 Trials were made with the kite- balloon, a captive balloon 

 which, unlike the ordinary spherical one, is not driven down or 

 carried away by strong winds. It is a German invention, and 

 is used in the army for reconnoitring. The Strassburg balloon, 

 which is of smaller construction, is the first adapted for lifting 

 self-recording meteorological instruments. — Results of meteoro- 

 logical observations for June at Camden Square (London) for 

 forty years, 1858-97. The mean of all the maximum tempera- 

 tures is 7i°'3, and of the minimum, 50° 9. The mean rainfall 

 is 2 23 inches ; in June of the present year the total fall was 

 I • 1 1 inches only. 



SOCIETIES AND ACADEMIES. 



London, 



Royal Microscopical Society, June 15. — Mr. E. M. 

 Nelson, President, in the chair. — The President referred to the 

 loss the Society had experienced in the death of Mr. Henry 

 Perigal, who died at the advanced age of ninety-eight. He then 

 exhibited and described two old microscopes, one of which, 

 made by Benjamin Martin, probably dated from about 1770. 

 It had two concave mirrors, one of 4" and the other of 9" focus. 

 The optical part was curious, having a fixed back lens in the 

 tube which was common to all the objectives, each of which was 

 fitted with a lieberkuhn. The other was an antique instrument 

 with simple lenses fitting into one another to increase the power. 

 It seemed to be a copy of one made by Mann and Ashcroft 

 somewhere about 1740, and was made by Cary. He next 

 called attention to an excellent lithographic portrait of Prof. 

 John Quekett, the work of Wm. Lens Aldous, whose son had pre- 

 sented it to the Society. — Mr. Frederick Ives exhibited acamera 

 lucida which he had devised. It was one he had obtained from 

 Messrs. Swift, and he had slightly modified it by depositing on 

 one of the inside faces of the compound prism a very thin specular 

 film of silver, through which it was possible to see the pencil 

 without having to centre the eye, as was the case where the film 

 was opaque with a small hole in it to look through. After some 

 remarks by Mr. Beck, Mr. Swift said there was a difficulty in 

 centring the eye in the old form which did not exist in the one 

 before them, the pencil being seen with ease while delineating 

 the object under observation. The President thought the device 

 a valuable one, and preferable to that of a thick film of silver 

 with a hole in it. — Mr. Ives also exhibited a monochromatic 

 green screen, consisting of dyed films between two plates of 

 glass, which he thought possessed advantages over liquid screens. 

 The one now shown would cut oft' all beyond the F line on the 

 blue side, including the ultra-violet, and also all red and yellow. 

 In reply to an inquiry, Mr. Ives said that of course the light 

 was not strictly monochromatic ; it was a mixture of pure green 

 in the spectrum at the E line, with some yellow-green on one 

 side and blue-green on the other. — Mr. B. W. Priest exhibited 

 a large number of slides of sponges. He said "he had brought a 

 selection which would be found to be characteristic of the order 

 Calcarea and the three sub-orders of Silicea, viz. the Monax- 

 onidit, Tetractinellida; and Hexactinellidae, to the last of which 

 he directed attention on account of their great beauty. There 

 were also some slides of fresh- water sponges.— The Secretary 

 said there was a paper of great interest, namely, the continua- 

 lion of Mr. Millett's report on the Foraminifera of the Malay 

 .'Vrchipelago, which being of a very technical character he pro- 

 posed should be taken as read. — The President reminded the 

 1 ellows present that the next meeting of the Society would not 

 take place until October l^. 



Mineralogical Society, June 21. — Prof. A, H. Church, 

 F.R.S., Vice-President, in the chair. — Prof. Miers com- 

 municated an account of some minute cubic crystals of lead 

 developed by the action of acid upon the surface of cast 

 lead. These, although too small to be isolated and measured 

 individually, were. successfully measured by means of the new 



NO. 1500, VOL. 58] 



double-circle or " theodolite "-goniometer, by which all the 

 faces of a complicated crystal may be determined in a single 

 operation. — Mr. E. G. J. Hartley read an account of an analysis 

 of Cornish Chalcophyllite, carried out in the Mineralogical 

 Laboratory at Oxford. This mineral, hitherto supposed to be a 

 basic arsenate of copper and aluminium, he found to contain no 

 less than 7 per cent, of SO;,, which has been overlooked by pre- 

 vious analysts, so that Chalcophyllite must now be classed 

 among the double arsenates and sulphates. — Mr. G. F. H. 

 Smith gave a short account of a possible dimorphous form of 

 Laurionite. In general appearance this mineral is very similar to 

 Laurionite, but on crystallographic and optical examination was 

 found to be monosymmetric. imitating rhombic symmetry by 

 twinning ; whereas Laurionite is truly rhombic. From an 

 analysis, made on a small quantity of selected material, Mr. G, T, 

 Prior found the chemical composition to be the same as that of 

 Laurionite. — Mr. Tutton exhibited a new dilatometer designed 

 for the purpose of measuring the thermal dilatation of crystals 

 by Fizeau's delicate method. In this instrument the expansion 

 of the platinum-iridium screws which carry part of the apparatus 

 is exactly compensated by an aluminium block, so that the 

 dilatation of the crystal is measured directly, and comparatively 

 thin crystals can be employed for the experiments. 



Edinburgh. 



Royal Society, July 4. — Lord McLaren in the chair. — The 

 Gunning Victoria Jubilee Prize for 1893-6 was presented to 

 Mr. John Aitken, for his varied and important researches in 

 the physics of meteorology. At the request of the Council, 

 the Astronomer Royal for Scotland gave an address on the 

 total solar eclipse of January 21, 1898, with some account of 

 solar observation generally. Prof. Copeland began with a 

 brief statement of what is now known concerning the sun's 

 constitution, and indicated the lines along which an increase 

 of knowledge might fairly be expected from observations of 

 total eclipses. He then described the work his party had been 

 able to accomplish during the recent eclipse. The photographs 

 shown in illustration were chiefly from among those taken by 

 himself and his assistants, and included several of the corona 

 and protuberances and some fine spectrograms of the upper 

 parts of the photosphere of the eclipsed sun. These were 

 obtained with an instrument in which quartz prisms and lenses 

 were used, and the spectral lines could be traced as far as Q. 

 A careful examination would no doubt throw light on the heights 

 reached by the various glowing vapours. The Astronomer 

 Royal expressed his deep sense of gratitude to all who, both 

 officially and privately, had facilitated his labours. — Dr. R. H. 

 Traquair communicated three papers (i) on a new species ot 

 Cephalaspis found by the Geological Survey of Scotland in the 

 Old Red Sandstone of Oban ; (2) on Thelodus Paget (Powrie) 

 from the Old Red Sandstone of Forfarshire ; (3) report on fossil 

 fishes collected by the Geological Survey of Scotland on the 

 Upper Silurian rocks of the Lesmahagow district. In this 

 report four new genera and eight new species of fossil fish were 

 described. The remains were in a remarkably good state of 

 preservation, and threw a new light on several important 

 biological problems. Thus certain scales, which had been 

 previously described as sharks' teeth, were proved incontestably - 

 to belong to forms of Thelodus ; and these forms also showed^ 

 that Powrie's Cephalopteris was a Thelodus (subject of second! 

 paper). The characteristics of the new genera Lanartia ancf 

 Birkenia were described at length, one peculiarity of the latter 

 being the direction of the scales, which was from above down- 

 wards and forwards, instead of from above downwards and 

 backwards, as in Ganoids. — Dr. W. Aitchison Robertson read 

 a paper on the effect of mixed diet as regards salivary diges- 

 tion. Among the results obtained may be mentioned the fol- 

 lowing : Porridge, especially if diluted with water or milk, 

 was rapidly digested. Potatoes in a powdered state were also 

 easily digested. Newly-baked bread was not so rapidly acted 

 upon by saliva as stale bread, but the ultimate degree of starch 

 conversion was greater in the former than in the latter. 

 Alcohol retarded salivary digestion of starch, but not so much 

 as infusion of tea. Wines had a marked inhilsitory action ; but 

 beer aided digestion. 



Paris. 



Academy of Sciences, July 18.— M. Wolf in the chair.— 

 Researches on the relations which exist between luminous and 

 chemical energy, by M. Berthelot. An experimental study of 

 the action of sunlight upon concentrated nitric acid, iodic 



