January 24, 1895] 



NA TURE 



299 



large basement rooms, one used chiefly for electrical and mag- 

 netic measurements, and one reserved for the practical classes. 

 On the floor above are the lecture theatre and smaller class- 

 room, apparatus room, chemical room, &c. The laboratories 

 are lighted in the main with electric light, the direct current, 

 supplied by the St. Pancras Vestry, being also used to charge a 

 set of about fifty accumulators. A collection of apparatus was 

 on view, more especially that designed for educational experi 

 ments, and used by students in the practical classes. Some of 

 the pieces shown were of historical interest, among them being 

 various instruments designed and used by Ritchie, who was 

 formerly Professor of Natural Philosophy in the College. 



On Thursday last, January 17, the French Society of Aerial 

 Navigation inaugurated the lectures to be delivered to the 

 pupils of the newly-established school of aeronautics. During 

 an address, Prof. Cornu, who was in the chair, said that he was 

 glad that the .-Vcademy of Sciences had always exhibited an 

 interest in aerial navigation. In 1782, a programme was drawn 

 up of experiments to be conducted with the help of balloons. 

 In 1794, there was established at Meudon the first aeronautical 

 school, and the first captive balloons were made. In 1802, 

 Gay-Lussac and Biot made the first scientific ascents, which re- 

 mained almost unequalled until sixty years afterwards, when 

 Glaisher took his aerial travels. The first dirigible balloon was 

 constructed in 1870. Later, Paul Bert investigated the condi- 

 tion of human life at high aUitudes. With these lacts before 

 them, the pupils of the French aeronautical school were re- 

 minded that their efforts would always be supported by the 

 Academy. Aeronautics had been always popular in France, 

 and had rendered good services to science and to the country. 



Some forgotten pages of photographic history were brought 

 before the Brixton Camera Club, by Mr. W. H. Harrison, on 

 January 15. It was pointed out that the many photographic 

 researches of Foucault have been so completely overlook ed that 

 in scarcely any recent photographic history is mention to be 

 found of more than his name, if so much as that. Fouc.auh's 

 early experiments in photographing the spectrum upon daguer- 

 reotype plates are interesting, and his results were not com- 

 plicated by the presence of collodion, gelatine, or other col- 

 loids. In those early days photographers were so anxious to 

 improve processes and to quicken them for purposes of por- 

 traiture, that perhaps these researches in the higher branches of 

 photography inierested them little, and soon afterwards were 

 forgotten entirely, so that the name of Foucault as a pioneer of 

 photography has practically passed out of the literature of the 

 subject for nearly a generation. H. liiyard, the first to exhibit 

 a selection of photographs to the general public, in July 1839, 

 hasalso been much neglected in modern photographic literature. 

 By means of his process, direct positives could be obtained 

 without the intervention of a negative. Bayard's process seems 

 Ukely to initiate useful modifications at the present time, in the 

 easy production of reversed negatives. Sometimes it is now 

 facetiously said that ihe best place for backings to prevent halation 

 is on the front of the plate, meaning the use of a thick coating 

 of emulsion : perhaps on Bayard's principle something of the 

 kind may hereafter be done in a more literal sense. It should 

 be remembered that there are two kinds of halation, and that 

 one of them is due to reflection among the panicles of silver 

 haloid in the film itself. Perhaps something of especial benefit 

 in astronomical photography may hereafter be evolved from 

 Bayard's principle. Who knows but that it may hereafter lead 

 to the production of a new class of dry plates which can be 

 freely exposed to light, and, when required lor use, sensitised by 

 an alcoholic or other volatile liquid containing a haloid salt, to 

 enable the re-drying to be elTected quickly ? 



NO. 1317, VOL. 51] 



Dr. a. MacDonald, of the U.S. Bureau of Education, has 

 sent us a number of statistics, showing the sensibility to pain, 

 by pressure, in hands of individuals of diflferent classes, sexes, 

 and nationalities. So far as they go, the results indicate that 

 the majority of people are more sensitive to pain in their left 

 hand than in the right. Women appear to be more sensitive 

 to pain than men, but of course it does not necessarily follow 

 that women cannot endure more pain than men. American 

 professional men are more sensitive to pain than American 

 business men, and also than English or German professional 

 men. The labouring cl.asses are much less sensitive to pain than 

 the non-labouring classes, and the women of the lower classes 

 are much less sensiiive to pain than those of the better classes. 

 The general conclusion is that the more developed the nervous 

 system, the more sensitive it is to pain. It is worth remark 

 that, while the thickness of tissue on the hand has some 

 influence, it has by no means so much as one might suppose, 

 a priori; for many with thin hands require much pressure 

 before experiencing any pain. 



An auriferous quartz-vein has been met with near Douglas 

 in the Isle of Man. This seems to be the first recorded dis- 

 covery of gold in that island, though, in view of its presence in 

 the very similar districts of Merioneth and Wicklow, it is not 

 in any way surprising. 



Electrical Discovery is the title of a new fortnightly journal, 

 in which it is intended to publish information on electrical 

 patents filed in the British Patent Office. The Official Journal 

 famishes short abstracts of such inventions, but these do not 

 appear until after the period for opposing the grants of the 

 patents has expired. The new journal is designed to supply 

 the need, by giving electricians early abstracts of all patent 

 specifications and amendments relating to electricity. Digests 

 and reports of patent cases of interest to electricians will also 

 be included, and an index of articles on electrical subjects. 



A FEW years ago it was practicable for persons of moderate 

 income to subscribe to all the periodicals devoted to engineering 

 and allied sciences, and to keep abreast with the contents. 

 Now the number of such journals is^ so great, and so many are 

 the memoirs and works bearing on engineering, that engineers, 

 like the rest of ui, are feeling the need of an index of their 

 literature. Suggestions for the construction of such an index 

 are given by Prof. G. D. Siephardson in the Transactions of 

 the American Institute of Electrical Engineers for November 

 1894, and the following number contains a report of a long 

 discussion on the subject. It is a satisfactory sign of the 

 development of the scientific side of engineering, that 

 electrical, mechanical, hydraulic, civil, and mining engineers 

 want an index to their literature. 



The great Andalusian earthquake of December 25, 1S84, as 

 is now well known, produced slight disturbances of the mag- 

 netic curves at Lisbon, Pare St. Maur, Greenwich, and 

 Wilhelmshaven. Two astronomical clocks were also stopped 

 at the observatory of San Fernando, near Cadiz. From the 

 times so recorded, the French Commission appointed to study 

 the earthquake obtained values which seemed to show that the 

 velocity of the earthquake wave diminished as it radiated out- 

 wards. In two recent papers (A'. AccaJ. dei Lined, Rend. 

 iii. 1894, pp. 303-310. 3'7-325). l^r. G. Agamennone recon- 

 siders the problem. He shows that the apparent diminution of 

 velocity would disappear if the time at Cadiz were a minute too 

 late. And an error of this kind, he remarks, is possible, for 

 the times given for the magnetic observatories correspond to the 

 beginning of the movement, whereas the clocks .-it Cadiz would 

 be stopped during a later phase. Assuming the velocity uniform, 



