July 19, 1877] 



NA TURE 



■37 



On July 13 the French Minister of Public Works visited the 

 works of the 187S Exhibition, which are in course of progression 

 at the Champ de Mars, The number of workmen engaged 

 in actual workicg was 1,137. Not less than 700 were employed 

 at the Central Pavilion. 



A SINGULAR accident has been recorded by the Journal 

 Officiel. M. Gastard, of Paris, had placed a number of car- 

 tridges on a table. .Some solar rays having been concentrated by 

 an " eye " in the glass of a window, a terrific explosion took place. 

 Similar catastrophes are more common than is generally supposed 

 in summer, the windows of railway carriages, igniting some- 

 times overdried plants, or even leaves fallen on railway embank- 

 ments. It is known also that fires sometimes occur in Algerian 

 forests through drops of water suspended to the leaves and 

 forming lenses. 



It is now about a quarter of a century since the first submarine 

 cable was laid, and the telegraph system may now be said to 

 embrace all parts of the world, offering a certain completeness 

 as an object of study. In an interesting broihure recently ssnt 

 us, " Recherches sur la Loi du Mouvement Telegraphique Inter- 

 national," M. Madsen sets the problem, — Is there a determinate 

 relation between the international telegraphic movement and the 

 commercial traffic, and what is the mathematical expression of 

 this relation ? lie arrives, from a comparison of statistics, at 

 a law which may be approximately expressed by the equation. 



of telegrams between two countries, d the distance between 

 their commercial "centres of gravity," f'the value (in pounds 

 sterling) of their commerce with each other, A^ the tonnage of 

 the ships sailing between them, A'j the tonnage of ships of the 

 one country (Z), but sailing between the other Zj and other 

 countries ; N^ the tonnage of ships belonging to Zj, but sailing 

 between Z and other countries. The law has various applica- 

 tions, some of which M. Madsen points out. 



An ingenious new registering thermometer devised by M. 

 Ilerve Mangon, is described in La Nature, A long and fine 

 capillary tube bent on itself and containing mercury, is supported 

 in an iron frame ; it passes through the stopper of a bell jar and 

 terminates vrith a fine point in a mercury dish placed in one scale 

 of a balance ; the other scale contains a vessel of glycerine 

 communicating by glass and india-rubber tubing with another 

 glycerine vessel on the same level in an adjoining frame. When, 

 on rise of temperature, mercury is forced out into the vessel, the 

 balance is depressed on one side and an electric contact made, 

 affecting an electro-magnet in the regi, tering apparatus, which is 

 composed of M. Redier's double wheel wiik with differential 

 train (which we must not stay to describe). When the depression 

 referred to has occurred a suspended float in the second glycerine 

 vessel descends, and raises the glycerine in the first, increasing 

 the weight in that scale. The curve obtainc d (from a pencil on 

 moving paper) is of zigzag form, the wheel-work being in 

 constant motion, now to the right, now to the left. 



M. Bertrand having lately made an appeal to possessors of 

 letters from Gauss, with a view to publishing the complete 

 works of the eminent geometer, the grand-daughter of Laplace 

 has responded with five interesting letters. One of them, written 

 in 1807, presents Gauss at the outset of his career, deprived of 

 his fortune and threatened with extreme measures if he did not 

 pay 2,000 francs as a war contribution to the French army 

 occupying Gottingen. In his distress he applies to Laplace, 

 thinking his intervention might prove effectual. At the same 

 time he describes the equally sad position of his colleague 

 Harding. Laplace, unable to influence Napoleon, pays the 

 2,000 francs, and begs his friend not to disquiet himself further. 

 Meanwhile Gauss obtains the sum from Olber, and now he is in a 



position to succour Harding. Two years later he paid Laplace 

 back the sum he had borrowed. 



Ax analysis has been lately made by Dr. Alder Wright 

 (Chemical Nt-ws) of two samples of wine, "ruby " and " white," 

 from the Auldana vineyards. South Australia, with a view to 

 determine the proportion of iron as a natural constituent. The 

 average amount obtained by one method was, in both cases, 

 o'ooi30, by another method o'ooi46, the iron being calculated 

 as FtO (in the former case it is thought there may have been a 

 little loss through incineration, &c.). Two circumstances are 

 noted ; first, that contact of the grape-juice with ironwork of any 

 kind is studiously avoided in the manufacture ; secondly, that 

 the soil of the Auldana vineyard is exceptionally ferruginous, 

 and as iron is taken up from the soil by vegetation, this seems a 

 probable cause for the occurrence of iron in the finished wine. 

 The identical character of the values, too (the wines being of 

 different vint.ages) makes it improbable that the source of the 

 iron is outside the grape-juice. 



An interesting experiment with regard to the speed of pigeon 

 flight was made the other day. A carrier pigeon having been 

 let off in Dover simultaneously with the starting of the express 

 fjr London, reached the latter place twenty minutes in advance 

 of the train. This corresponds to a distance-difference of 

 eighteen miles. 



We observe that the recent enlightened decision by the Senate 

 of London University with regard to admission of women to 

 degrees in medicine meets with a good deal of hostile criticism 

 from some of our leading medical contemporaries. We feel sure 

 that no Trades' Union spirit will be allowed to prejudice what 

 must generally be recognised as a step in the right direction. 



At a meeting of members of the Birmingham Natural His- 

 tory and Microscopical Society, held at the Midland Institute on 

 July 13, a committee was appointed to make arrangements for 

 another marine excursion, somewhat similar to the one made by 

 this society in 1S73 to Teignmouth, but this time it is to be to 

 Arran and the Western Islands of Scotland. The dredging will 

 be carried on in Lamlash and Brodick Bays. At the same time 

 excursions will be made on land to Arran and the adjacent 

 localities, all of which, we believe, yield a number of rare speci- 

 mens, both botanical and geological ; so that the members of 

 each section no doubt will find this an enjoyable and an in- 

 teresting excursion. '?It will take place in the first week in 

 September. 



A WONDERFUL white aquamarine has been found in Penh- 

 shire which, when cut, has produced one of the most brilliant 

 gems ever seen. It is said by many competent judges to be 

 equal to her Majesty's celebrated Koh-i-noor, its refraction being 

 very great both by day and night. It is of a pure pellucid liquid 

 white, and is known as the Scotch Koh-i-noor. Its hardness is 

 80, and specific gravity 276. Mr. Bryce M. Wright, F.R.G.S , 

 is its possessor. 



The additions to the Zoological Society's Gardens during the 

 past week include a Simbur Deer [Cirvus aristotdis), a Spotted 

 Porcine Deer {Cerviis minor') from India, presented by H.R.II. 

 the Prince of Wales, K.G. ; a Slow Loris (Nycticebus tardigra- 

 dtis) from Malacca, a Prehensile- tailed Vsirsidox\i-is(Pai-adoxurus 

 prelieiisilis) from Burmab, presented by Mr. W. H. Richardson; 

 a Leadbeater's Cockatoo [Cacatua leadbeateri) from Australia, 

 presented by Mrs. Shand ; a Red Howler (Mycetes senindus) 

 from New Granada, four Axis Dee"/ (Cervus axis) from India, 

 a Merian's Opossum [Didelphys dorsigera) from South America, 

 deposited ; two Striped Hyasnas (Hyiena striata), born in the 

 Gardens, a Black-necked Swan (Cygnus ni^ricollis), hatched in 

 tlie t'rardens. 



