Oct. 12, 1882] 



NATURE 



585 



as the di-coverer of facts which have often thrown unexpected 

 light on the problems of our science, and have always, at least, 

 been oi the highest importance, and stated with admirable truth 

 and modesty.'' 



The Annates de Chimie et de Physique reproduces in its August 

 number a paper relating to the theory of dissipation of energy, 

 read by Macquorn Raukine at the British Association meeting 

 in 1852. 



A series of scientific ascents were made on Sunday afternoon 

 from the Place Saint Jacques, in Paris, under the auspices of the 

 Academie d' Aerostation Meteorologique. At a height of eight 

 hundred feet photographs of the entire horizon were taken by 

 means of a panoramic apparatus invented by M. Triboulet. In 

 a brief explanation of this, given by one of the members of the 

 Academy, it was pointed out that the experiment was as im- 

 portant from a military as from a scientific point of view, since 

 it would enable an army to ascertain exactly the number and 

 position of their enemies. At another ascent telephonic conver- 

 sation with persons on the ground was carried on at the height 

 of five hundred feet. The experiments were under the auspices 

 of the Municipal Council of Paris. 



The aurora borealis which was see;i in so many parts of 

 England on October 2, was also visible in France from a very 

 large number of places. 



M. Duvaux, the French Minister of Public Instruction, has 

 opened the first superior school for female^ established iu France. 

 It is situated in the city of Rouen, and the legular course of 

 study \\ ill begin this year. Many similar establishments are in 

 course of construction in several parts of the country. 



The additions to the Zoological Society's Gardens during the 

 past week include a Sykes's Monkey {Cercopithecus albigtilarisl ) 

 from Eat Africa, presented by Opt. F. \Y. Schwedler ; a 

 Binturong (Areticlis Unturong) from Malacca ; a Common Fox 

 (Canis vulpes 9 ), British, presented by Mrs. Studholme Brownrigg; 

 two Goshawks (Astur palumbarius) from Germany, presented by 

 Dr. Rudolph Blasius, C.M.Z.S. ; a Common Raven {Corz/ux 

 corax), two Lesser Black-backed Gulls (Lams fuse us) froai Scot- 

 land, presented by Mr. F. G. Bury ; two Greater Sulphur-crested 

 Cockatoos (Cacatua galerita) from Australia, presented by Mr. 

 C. Kerry Nicholls, F.Z.S. ; a Puff Adder (Vipera arietans) ftom 

 South Africa, presented by Lieut. R. Crawshay ; an Ornamented 

 Lorikeet ( TricAogiossus oriiatus) from Moluccas, a Crested Curas- 

 sow (Crax a ecior) from Guiana, two Illiger's Macaws (Ara mora- 

 cana) from Brazil, purchased ; two Brazilian Hangnests {Icterus 

 jamaicai) from Brazil, deposited ; an Australian Fruit Bat 

 (Pteropus folioeepkalus), born in the Gardens. 



CHEMICAL NOTES 

 An exceedingly ingenious patent for the manufacture of 

 hydrogen and oxygen has been taken out by M. N. A. Helouis, 

 of Paris. Wood charcoal is obtained by heating wood in closed 

 vessels : the gas which is evolved is u-ed for heating the retorts 

 in which hydrogen and oxygen are produced, the tar is used for 

 carburetting hydrogen, the lyroligneous acid is employed to 

 decompose sodium sulphite (produced in another stage of the 

 process*, whereby sulphurous acid and sodium acetate are ob- 

 tained. By passing steam over hot wood charcoal, a mixture of 

 hydrogen, carbon monoxide, and dioxide is obtained ; the mixed 

 gases are passed into retorts containing heated gypsum, which is 

 reduced by carbon monoxide to calcium sulphide ; the escaoing 

 carbon monoxide is absorbed by soda solution, giving sodium 

 bicarbonate. Oxygen is obtained by decomposing gypsum (600 

 parts) by silica (340 parts river sand) ; the mixture ot sulphur 

 dioxide and oxygen which is produced, is passed into caustic 

 soda solutior, whereby sodium bisulphite is formed ; the resi- 

 dual sulphur dioxide is absorbed by milk of lime. The calcium 

 sulphite produced by the final washing of the mixed gases is 

 decomposed by sodium bicarbonate, giving calcium carbonate 



and sodium bisulphite ; the latter is decomposed, as already 

 described, by pyroligneous acid, and the sulphurous acid pro- 

 duced is oxidised to sulphuric acid in a cylinder containing 

 platinised pumice-stone, by air containing 75 percent, of oxygen. 

 The calcium sulphide which remains in the oxygen retorts 

 is decomposed by carbon dioxide and steam ; the sulphuretted 

 hydrogen produced, after being freed from moisture by passing 

 through a condensing apparatus, is burned with air rich in oxy- 

 gen, and the sulphurous acid formed is conducted into the 

 leaden chambers of the sulphuric acid manufactory. Air con- 

 taining 75 per cent, oxygen is obtained by pumping air into a 

 cylinder containing a mixture of 80 parts water and 20 parts 

 glycerine ; when the pressure has reached 10 atmospheres, 

 communication is made between the first cylinder and another 

 from which air has been removed ; air rich in nitrogen remains 

 iu the first cylinder. By repeating this operation, a mixture of 

 75 per cent, oxygen and 25 per cent, nitrogen can be obtained. 

 Another method of obtaining nearly pure oxygen from air 

 consists in passing the latter into an iron cylinder containing a 

 bag of silk covered with caoutchouc ; the dialysed air is then 

 driven by a steam jet into a condenser, and thence passes into a 

 second similar cylinder ; this process is repeated several times ; 

 a mixture of 98 per cent, oxygen and 3 per cent, nitrogen may 

 thus be obtained, but for most metallurgical or lighting purposes 

 a mixture containing 60 per cent, oxygen is sufficient. Nitrogen 

 escapes from each iron cylinder by a side tube which dips under 

 water. The silk bags used for dialysing air are prepared by 

 washing ordinary caoutchouc with a mixture of carbon disulphide 

 and alcohol (whereby substances are removed which would 

 readily stop the pores of the caoutchouc-covered silk) making 

 into a paste with benzene, and placing a layer of this between 

 two layers of silk. 



In the Seienhfic Proceedings of the Ohio Mechanics' Institute 

 (1. 35) a process is described for melting iridium by heating in a 

 Hessian crucible with phosphorus, and subsequent renewal of 

 the phosphorus by repeated fusion with lime. The metal, in 

 very thin sheets, can be cut by a copper wheel making 2000 

 revolutions per minute, and having its surface covered with 

 emery, or corundum, and oil. Metallic iridium is nearly as hard 

 as ruby ; no steel tools make any impression on it ; attempts 

 have been made, with fair success, to u 5 e it in place of carbon as 

 the negative pole in the electric arc light. 



It is stated in the Chemical Review that recent analyses of the 

 water from the Holy Well at Mecca, which is so eagerly drunk 

 by pilgrims, show this water to be sewage, about ten times 

 stronger than average London sewage. 



Artificial ivory of a pure white colour, and very durable 

 has recently been manufactured by the inventor of celluloid : it 

 is prepared by dissolving shellac in ammonia, mixing the solution 

 w ith oxide of zinc, driving off ammonia by heating, powdering, 

 and strongly compressing in moulds. 



ON THE ALTERA TIONS IN THE DIMENSIONS 

 OF THE MAGNETIC METALS BY THE ACT 

 OF MA GNETISA TION " 



DR. fOULE long since discovered that when a bar of iron was 

 magnetised by an electric current, an elongation of the bar 

 took place. In subsequent experiments, published in 1847, Joule 

 found that the elongation amounted to about I -200,000th of the 

 length of the bar for the maximum magnetisation, and that the 

 total elongation was nearly proportional to the square of the 

 actual magnetisation. By placing the bar in a vessel of water 

 stopped w ith a capillary tube, it was found that the volume of 

 the iron did not augment, and hence Joule concluded that the 

 sectional area diminished in proportion to the elongation. Under 

 longitudinal tension, magnetisation caused a shortening of the 

 rod when the tension exceeded 600 lbs. for a rod a quarter of an 

 inch square. Soft steel behaved like iron : but hard steel, under 

 all circumstances, Joule found to shorten slightly when the mag- 

 netising current passed 



I111073 Prof. Mayer repeated Joule's experiments with new 

 and delicate apparatus ; the elongation of the iron he found to 

 amount to i-277,oooth of its length for the maximum magnetisa- 

 tion. Mayer also found that soft as well as hard steel contracted 

 under magnetisation. 



1 Paper read at the Southampton Meeting of the British Association by 

 Prof. W. F. Barrett, F.R.S.E., Professor of Physics in the Royal College 

 of Science, Dublin. 



