56o 



NATURE 



{_April 17, 1879 



M. Marie Davy, the director of Montsoiiris Meteorological 

 Observatory, has set up a registering Thomson electrometer. 

 The indications are recorded by photography in accordance with 

 the system which has been established at Kew by the British 

 Association. A comparison of readings taken by these two 

 establishments will render essential services to the progress of 

 meteorology. M. Descroix, the observer in charge of this in- 

 strument, was assailed before the Meteorological Society by a 

 French savant who has invented another electrometer, in which 

 the registration is taken with a pencil and mechanical force. 

 But the discussion proved that such instruments are useless with- 

 out knowing whether their indications are worth being recorded, 

 as many objections can be raised against their use and have been 

 published by competent electricians. 



The French artists are preparing for an Exhibition of Fine 

 Arts, to be held as usual in the Palais de 1' Industrie from the be- 

 gimiing of May. When this exhibition is over a scientific exhi- 

 bition will be organised by M. Nicolle, the successful organiser 

 of the Exposition Maritime et Coloniale held in the same building 

 in 1877. M. Jules Simon, M. du Moncel, and others are taking 

 an active part in the preparations. The chief peculiarity will be 

 the execution of all the scientific experiments capable of being 

 made before an audience and on an unusual scale. The organiser 

 will try to fill the lacuna, which was so much complained of in 

 the last Champ de Mars exhibition. 



A CORRESPONDENT of the Hiogo News mentions that in the 

 city of Kioto there are to be seen many semi-foreign buildings 

 which are the Shogakko, or elementary schools. Of these there 

 are 64 in the city, and 445 in the whole fu. Kioto is divided 

 into two large districts, called Kami and Shimo Kiyo, which are 

 subdivided respectively into 33 and 32 ku. Each ku is obliged 

 to establish and maintain one of these schools, except in the case 

 of poor ku, w hen two are allowed to unite and form one school 

 district. Besides the usual Japanese course of studies, the 

 pupils are taught the elements of foreign mathematics, history, 

 geography, and philosophy, and they are also trained in 

 gymnastic exercises. Education is compulsory, only those (who 

 are of age) being exempted who are necessary to the support of 

 their parents. 



n We learn that the organisation of the captive balloon has been 

 altered by M. Giffard. The aeronautical and scientific staff has 

 been [constituted by him into a private company. He has 

 placed at their disposal the _funds required for the working 

 of the balloon, and placed the enterprise in their own hands on 

 their own responsibility and care. This arrangement has been 

 agreed to by the public authorities, and will leave a handsome 

 surplus on behalf of the men who spend their lives in the aeronau- 

 tical career, as a large part of the profits, exclusive of a handsome 

 weekly pay, is to be divided by equal part amongst them. A 

 few important alterations have been made in the car, and ring, 

 and netting. The net ascending power Mill be enlarged by a 

 ton. A kind of india-rubber gas-meter, containing 100 cubic 

 metres, has been constructed, in order to render inflation instan- 

 taneous between two ascents. 



The Academic des Ascensians Meteorologiques opened its 

 Museum in Paris on April 3. More than 600 persons 

 visited the gallery. It is to remain open every Tliursday, and 

 any day admission may be obtained by letter to the General 

 Secretarj', 50, rue Rodier. The number of exhibitors exceeds 

 120. Amongst the collection of aeronautical medals we note 

 some commemorating ascents made in England in the end of the 

 last century. A registering barometer for ascents to 5,000 

 metres is exhibited by MM. Richard freres ; it was purchased 

 by the government for the Meudon aeronautical establishment. 

 M. Egasse exhibits an apparatus for filling balloons with 

 hydrogen extracted by the action of zinc and chlorhydric acid. 



The result of the reaction is employed in large quantities for 

 destroying miasmatic influence in barracks and other similar 

 establishments. A new paddle has been constructed for ascend- 

 ing and descending without gas or ballast when the balloon has 

 been placed on equilibrium vith surrounding air, a new guide 

 rope for diminishing the velocity by friction when the balloon is 

 travelling at sea, a safety-car for these perilous occasions, 

 difl'erential valves, &c. Lectures will be delivered and ascen- 

 sions executed by the members of the institution. 



The Cologne Gazette reports, under date the 9th inst., a slight 

 shock of earthquake at Buir and Elsdorf. The shock is stated 

 to have been noticed at five minutes past midnight. It had a 

 rolling noise and took an east-south-easterly direction. 



The Tijlis Messenger says that a strong earthquake was felt on 

 March 27 in Persia, at the Gulf of Miama. 



A general exhibition of the various systems and apparatus 

 used for electric lighting is to be held in the Royal Albert Hall 

 in May. An inaugural lecture, at which the Prince of Wales 

 has promised to be present, will be delivered in the evening of 

 Wednesday, May 7, by Mr. W. H. Preece. 



As an agitation prevails in France against the laws proposed 

 by M. Ferry for prohibiting the members of unauthorised bodies 

 from taking any part in public instruction, it is very likely that 

 Government will retain the exclusive right of conferring degrees,. 

 but the proposed restrictions will be rejected by Parliament. 



The following details (published by Herr Landauer in the 

 Reports of the Berlin Chemical Society) regarding the behaviour 

 of safranine when spectroscopically examined, may interest the 

 readers of our recent article on " Absorption Spectra " (vol. 

 xix. p. 495). It is well known that the salts of safranine show 

 the remarkable reaction that the red colour of their solutioii 

 turns into violet, indigo-blue, bluish green, and finally emerald 

 green, upon addition of concentrated acids, particularly of sul- 

 phuric acid. The change of colour takes place in the opposite 

 direction if safranine is dissolved in strong acids and water is- 

 gradually added to the solution. If these solutions are ex- 

 amined with the spectroscope, then it appears that each of the 

 colours mentioned shows a separate spectrum. The green solu- 

 tion absorbs the violet, blue, and red rays, the bluish-green one 

 behaves in the same way, but lets a part of the red rays pass j 

 the blue solution absorbs only the yellow rays, and the more the 

 colour of the solution turns violet and red through the addition 

 of water, the more the absorption passes over to the green part 

 of the spectrum. Herr Landauer attempted to determine the 

 cause of these changes of colour in the liquid, and the corre- 

 sponding alteration of the spectrum. Finding it difficult, how- 

 ever, to isolate the various chemical compounds formed in the 

 liquid, it was only possible to try an explanation from the che- 

 mical behaviour of the liquid itself. Finally he arrived at the 

 conclusion that of the two possibilities, formation of different 

 acid salts, or of different hydrates of the same salt, the latter is 

 the more probable one. The change of colour takes place also 

 when the solution is evaporated, and reappears in the opposite 

 direction when water is again added. The sulphate is the most . 

 characteristic salt of all; blotting-paper impregnated with a 

 solution of this salt, and dried by heating until it has become 

 green, soon becomes blue by attracting moisture from the atmo- 

 sphere, and a drop of water thrown upon it instantly gives a 

 red stain m ith a blue margin. Herr Landauer supposes that 

 there exist three different hydrates (or two hydrates besides an 

 anhydrous salt), which are red, blue, and green respectively, the 

 violet and bluish-green tints resulting from mixtures of these. 

 Herr Vogel's maxim, therefore, that the rule "each body has 

 its own spectrum" can be admitted only with restrictions, may 

 be still further restricted, inasmuch as it may be asserted that 



