April 19, 1894] 



NA TURE 



accumulate under continually increasing pressure, the liquid 

 being forced up the reservoir tube, and under this higher 

 pressure the liquid is able to take up more chlorine, and hence 

 a portion of the rising gas is absorbed. This difficulty is 



overcome by adopting the following arrangement : — The two 

 ■collecting tubes, joined as usual by a connecting cross tube near 

 their lower ends, are made shorter than usual and without taps. 

 The upper end of each is connected by a ground joint or a piece 

 of thick caoutchouc tubing with a delivery tube bent outwards 

 horizontally at a little distance above the joint ; each delivery 

 tube is sealed, a few inches along the horizontal limb, into a three- 

 way tap which forms the summit of a measuring cylinder standing 

 in a glass trough, and upon the other side of the tap the delivery 

 tube is continued for a short distance as an exit tube. The carbon 

 electrodes are not cemented in glass enclosing tubes, but merely 

 closely fitted with loose enveloping tubes, in order to prevent 



.^xmixture of the gases in the connecting cross tube. In order 

 to carry out the experiment the electrolysis vessel is three- 

 fourths filled with ordinary strong acid, the delivery tubes 

 attached, the glass trough on the cathode side nearly filled with 

 water, and that on the anode side with chlorine water. By 

 attaching an aspirator, conveniently in the form of a caoutchouc 

 ball, to the short exit tube attached to each three-way tap, the 

 liquids in the troughs may be drawn up to the tops of the 

 measuring cylinders ; when this is achieved the aspirator is 

 removed, and the taps so arranged that the measuring vessels 

 are shut off and the electrolysis apparatus is open to the air. 

 The electrical circuit is then completed, and the gases allowed 

 to escape for a few minutes, during which they may be shown 

 to be chlorine and hydrogen, the former by its action upon 

 starch and potassium iodide paper, or indigo solution contained 

 in a test tube held under the mouth of the exit tube, and the 

 latter by collecting a quantity in another test-tube held above 

 the open end of the other exit tube, and igniting the gas. Both 

 taps may then be simultaneously turned so as to shut off the 

 electrolysis apparatus from the air, and connect it with the 

 measuring cylinders, when the gases will rapidly fill the latter 

 to precisely the same extent. When sufficient has accumulated 

 the current may be switched off, or the measuring vessels closed 

 by suitable movement of the tap, and the volumes of the two 

 gases shown to be exactly equal. 



Further details of the preparation of the salts of di- 



NHo 

 amidogen, hydrazine, | , from the interesting diazo-deriva- 

 NH., 

 N... 

 tive of acetic acid, i| .CH . COOII, are given in the current 

 N/ 



number of the j5friV/z/^ by Prof. Curtius and Dr. Jay. Diazo- 

 acetic ether is first prepared, essentially as follows. Equal 

 weights of chloracetic acid and ammonium chloride are dissolved 

 in water, and twice as much powdered lime added by vlegrees, 

 so as to avoid undue heating. After standing the liquid is 

 saturated with hydrochloric acid and converted by evaporation 

 over the water bath to a yellow solid. This product is subse- 

 quently dissolved in alcohol and again saturated with hydrochloric 

 acid gas, after which the alcohol is removed and the residue dis- 

 solved in water. In order to diazotise it sodium acetate is first 

 added, so as to modify the action of sodium nitrite, then ice and 

 sodium nitrite, when diazoacetic ether is formed and may be 

 extracted by means of ether. In order to obtain the hydrazine 

 salt from diazoacetic ether, the latter may be reduced either 

 with ferrous sulphate and soda or zinc dust and soda, the former 

 reducing agent being preferable, and affording 92 per cent, of 

 the theoretical yield. Upon acidification with the acid whose 

 hydrazine salt is required, the salt in question is pro- 

 NO. 1277, VOL. 49] 



duced. The theory of the reaction is that hydrazoacetic acid, 



I /CH. COOII, is formed upon reduction of diazoacetic 

 WW 



ether in alkaline solution, and that this substance is decomposed 

 by acids with formation of a salt of hydrazine and glyoxylic 

 acid. Thus, with sulphuric acid hydrazine sulphate is produced 

 as follows : — 

 HN. CHO 



I ^CH.COOH-i-H.,S04 + H.O = N.,H4.HoS04-f | 

 HN'^ ' ' ' COOH 



The silver salt of the unstable hydrazoacetic acid has actually 

 been isolated from the liquid by action of silver nitrate. It is 

 an insoluble substance which yields crystals of hydrazine sul- 

 phate upon addition of dilute sulphuric acid and evaporation. 

 The glyoxylic acid byproduct has also been isolated in the form 

 of its hydrazone by addition of phenyl hydrazine. Hence the 

 above reaction, memorable as the one by which Prof. Curtius 

 first isolated di-amidogen, is now fully cleared up. 



The additions to the Zoological Society's Gardens during the 

 past week include a Rhesus Monkey {Macacus rhesus, i ) from 

 India, presented by Mr. Robert O'Callaghan ; a Ma- 

 caque Monkey {Macacus cynomolgus, ?) from India, pre- 

 sented by Mr. J. Pearson Callum ; a Meller's Duck {Anas mel- 

 leri) from Madagascar, presented by Mr. H. H. Sharland ; 

 a Rose Hill Parrakeet {Platycercus exitnms) from Tas- 

 mania, presented by Mrs. Carter; a Smooth Snake (Coro- 

 nella Icevis) European, presented by Mr. Ignatius Bulfin ; a 

 Cape Zorilla {Ictonyx zorilla) from South Africa, a Hairy 

 Armadillo {Dasypus villosus) from La Plata, two Rabbit-eared 

 Perameles {Peramdes lagoiis) from Western Australia, an 

 Adorned Ceratophrys ' {Ceratophrys ornala) from South 

 America, three White's Tree Frogs {Hyla Carula). four 

 Golden Tree Frogs {Hyla aurea) from New South Wales, 



deposited ; a Tayra {Galictis Barbara), a Coot {Fulica, sp. 



inc.), an Orange-chested Hobby {Falco fttsco-cczrulescens') from 

 South America, purchased ; a Bennett's Wallaby {Halmaturua 

 bennetti, 9 ) from Tasmania, received in exchange ; three 

 Raccoons ( Procyon lotor), a Crested Porcupine {Hystrix cristata), 

 born in the Gardens. 



OUR ASTRONOMICAL COLUMN. 



The Presence of Oxygen in the Sun. — At the meeting 

 of the Paris Academy of Sciences on April 9, Dr. Janssen de- 

 scribed a convenient method of raising gases to a high tempera- 

 ture, used by him in connection with investigations on the 

 spectrum of oxygen. The question of the presence of oxygen 

 in the gaseous envelopes of the sun comes under two distinct 

 cases. In the first place, oxygen may exist in the exterior 

 parts of the corona, that is to say, in a medium where the tem- 

 perature approaches that of the terrestrial atmosphere. In this 

 case the spectrum of the gas would be similar to that which is 

 produced by our atmosphere, and, in order to prove its absence 

 in such parts of the coronal envelope, it is sufficient to show 

 that the lines and bands due to oxygen in the solar spectrum 

 are entirely produced, both as regards number and intensity, by 

 the earth's atmosphere. Dr. Janssen's observations from the 

 summit of Mont Blanc, and his experiments at Meudon, have 

 been made with a view of settling this point. But the ca-e of 

 observations on oxygen at ordinary temperatures only repre- 

 sents a part of the question. Any oxygen existing in the lower 

 portions of the corona, in the chromosphere, and in the photo- 

 sphere, must be at a high temperature, and in order to decide, 

 by means of spectrum analysis, as to whether it is present or not 

 in these solar layers, it is necessary to know the modifications 

 which the spectrum of oxygen undergoes when the temperature 

 of the gas is elevated. This research, however, is attended 

 with special difficulties. The absorption lines and bands of 

 oxygen are only produced by great thicknesses of the gas. The 

 B group, for example, only appears in the spectrum when a 



