June i, 1882] 



NA TURE A 



III.— Experiments Illustrative of Combustion 

 Phenomena 



A. Burning Oxygen in Sulphur Vapour.— A two- 

 necked balloon is fitted with corks, each carrying a tube, 

 one of which passes towards the bottom of the balloon, 

 and has its tip slightly bent upwards, the other, begin- 

 ning flush with the inner surface of the cork, passes 

 downwards into a cylinder containing water. The first 

 of these tubes communicates, by means of a long piece 

 of caoutchouc tubing, with a supply of dry oxygen. About 

 40 to 50 grams of dry sulphur are placed in the balloon, 

 and heated till the vessel is quite filled with reddish 

 vapours, the oxygen delivery tube being meanwhile with- 

 drawn. Oxygen is allowed to flow from the delivery tube 

 in a stream sufficiently rapid to cause a glowing chip of wood 

 held 2 to 3 millims. from the end of the tube to burst into 

 flame ; a small piece of charcoal is attached by platinum 

 wire to the tip of the oxygen delivery tube ; the charcoal 

 is ignited, and the cork carrying the tube which delivers 

 oxygen is inserted into the neck of the balloon. The 

 oxygen is soon seen burning in the vapour of sulphur 

 which fills the vessel ; the product of combustion, viz. sul- 

 phur dioxide, is led by the second tube into the water in 

 the cylinder, the presence of sulphurous acid in which is 

 easily exhibited (C. von Tham, loc. ei/.). 



B. Burning Sulphuretted Hydrogen in Vapour of 

 Nitric Acid.— to to 80 c.c. of concentrated nitric acid 

 (sp. gr. 1 -53) are placed in a flask of 500 c.c. capacity. A 

 rapid stream of sulphuretted hydrogen is passed, through 

 water, into the acid, whereupon red fumes are copiously 

 produced. The delivery tube is slowly raised from the 

 surface of the acid towards the neck of the flask ; at a 

 certain' distance from the acid the sulphuretted hydrogen 

 takes fire and burns with a blue flame ; the upper part of 

 the flask becomes filled with white fumes of sulpuric acid, 

 the lower part with red fumes of oxides of nitrogen, little 

 or no sulphur separating (Kessel, Beriehle, xii. 2305). 



C. Burning Ammonia in Oxygen. — A wide-mouthed 

 flask is fitted with a cork, which carries a tube passing 

 nearly to the bottom of the flask, and also a large straight 

 drying tube, which contains solid caustic soda and is 

 closed at its upper end by a cork carrying a little piece of 

 tubing drawn out to an opening about 2 mm. in diameter. 

 A quantity of strong ammonia liquor is placed in the flask 

 and heated nearly to boiling, the lamp is withdrawn, and 

 the cork with its tube inserted. A stream of oxygen is 

 passed into the hot liquor, and the dry ammonia, mixed 

 with oxygen, is ignited as it issues from the caustic soda 

 tube. As the amount of ammonia diminishes, the flame 

 becomes smaller, but very hot ; a piece of platinum wire 

 may be melted, or a lime cylinder may be caused to give 

 out much light, by holding it just above the central zone 

 of the flame (Rosenfeld, Beriehle, xiv. 2104, and xv. 169.) 



D. To show that Water is produced by Burning Hydro- 

 gen in Oxygen. — A small platinum flask (as is figured in 

 Roscoe and Schorlemmer's " Chemistry," I., p. 339) is 

 uirnished with a good cork carrying two tubes of ordinary 

 pipe-clay, which reach towards the bottom of the flask : 

 one of these tubes communicates by caoutchouc tubing 

 with a supply of dry hydrogen, the other with a supply of 

 dry oxygen. The exit-tube of the flask is attached to a 

 piece of glass tubing which connects with a glass worm 

 condenser, underneath which a beaker is placed. Dry 

 hydrogen is passed into the flask until the air is com- 

 pletely replaced from the entire apparatus : while this is 

 being done, the caoutchouc tubing which connects the 

 clay tube with the oxygen supply is securely clamped just 

 above its junction with the clay pipe, to prevent hydrogen 

 from diffusing backwards into the oxygen tubes,' and so 

 loaning an explosive mixture. When the air is all driven 

 out of the apparatus, the platinum flask is heated to red- 

 ness, dry oxygen is passed into it, and the lamp is with- 

 drawn. By properly regulating the streams of oxygen 

 and hydrogen, so much heat is produced that the flask 



becomes nearly white hot; water is quickly forme! and 

 trickles, and after a little, flows in a continuous stream 



[ through the glass worm into [the beaker beneath (Hof- 



■ mann. Beriehte, xii. 1122). 



E. Unbitrning of Water-gas by Iron and by Mag- 

 nesium. — 3-4 grams very finely divided iron (Ferrum al- 

 coholisatuni) are placed in a small piece of hard glass 

 tubing about 12 cm. long and 14 mm. diameter. One end 

 of this tube is connected with a flask containing hot 

 water, the other with an ordinary gas exit-tube and small 

 pneumatic trough. The iron is heated, the water brought 

 to, and just maintained at the boiling-point, and the end 

 of the delivery-tube is plunged under the water in the 

 trough. Hydrogen is obtained in a rapid stream. As 

 thus arranged the decomposition of water-gas by iron is 

 readily shown without the use of a furnace or porcelain 

 tube. 



A similar apparatus serves to show the decomposition 

 of water-gas by magnesium ; a piece of magnesium-ribbon 

 about 60 cm. long is folded on itself so as to form a bundle 

 about 1 cm. in length, which is placed in the glass tube; the 

 water is kept nearly boiling ; the magnesium is heated 

 until it begins to melt and burn at the edges, at this 

 moment the water is rapidly boiled (and the exit-tube is 

 plunged under the water in the trough), when the mag- 

 nesium is found to burn vividly in the steam and hy- 

 drogen to be evolved in quantity (Rosenfeld, Beriehte, 15, 

 160. M. M. P. M. 



NOTES 



We are glad to learn that one of the evening (Friday, August 25) 

 discourses at the .Southampton meeting of the British Association 

 will be given by Sir William Thomson, and that the subject will 

 be " Tides." Prof. Moseley's discourse on " Pelagic Life" will 

 be given on Monday evening, August 28. 



The honour of Companion of the Order of St. Michael and 

 St. George has been conferred upon Mr. W. T. Thiselton Dyer, 

 F.R.S., Assistant Director of the Royal Botanical Gardens, 

 Kew, for services rendered to Colonial Governments. 



The French Minister of Public Instruction has again ap- 

 pointed a Commission to direct the deep sea exploration of the 

 Atlantic in the Travaillmr in July and August next ; the inves- 

 tigation will include the ocean bed along the coasts of Spain, 

 Portugal, and Morocco. The members of the Commission are 

 MM. A. Milne-Edwards, L. Vaillant, E. Perrier, Marion, Folin, 

 a'ld P. Piscber. 



A Florence correspondent writes: — "On Sunday, May 

 21, the students and professors of the Faculties of Science 

 and Medicine of Florence assembled to celebrate the memory 

 of Chailes Darwin. The large aula of the "Istituto" was 

 crowded with auditors, and many had to be content with 

 standing-room in the corridor outside. An address was read by 

 the representative of the students, and an eloquent study of the 

 genius and character of the great man of science by Prof. Mante- 

 gazza. I was struck by the note of religious solemnity that 

 marked the proceedings." Similar testimonies of the high 

 veneration in which the name of Darwin is held abroad come 

 to us from other parts of Italy, as u ell as France, Germany, 

 Norway, and Russia. 



We lately noticed the death of Mr. T. Donovan, lecturer on 

 physiology and other scientific subjects at the Working Men's 

 College and at the Birkbeck Institution. We learn that he has 

 left a widow and two children, whose position has excited the 

 sympathy of some of those who know the value of the work he 

 did, and that a committee has been formed to collect a fund for 

 their assistance. Mr. R. B. Litchfield, Bursar of the Working 

 Men's College, whose address is 4, Bryanston Street, Portman 

 Square, W., is Treasurer of the Fund. 



