SCIENCE-GOSSIP. 



47 



which, out of respect for Dr. Hewitt, I will call 

 its normal or luminous phase. Under these 

 conditions the gas has been carefully analysed by 

 Mr. S. A. Woodhead, B.Sc. (Public Analyst for 

 Sussex and Professor of Chemistry at the Agri- 

 cultural College, Uckfield), and I here beg to record 

 my grateful thanks to Mr. Woodhead, who has 

 occupied much time and taken much trouble to 

 secure the accuracy of his determinations. He 

 constructed his laboratory on the spot at Heath- 

 field, an unlimited amount of gas being supplied to 

 him direct from the bore-hole by means of tubes, 

 and he has taken care to check his results. The 

 analysis, speaking roughly, agrees fairly well with 

 that of Dr. Hewitt respecting the presence of 

 Methane (or Marsh gas), but Mr. Woodhead's 

 analysis reveals the presence of certain hydro- 

 carbons which, from an illuminating point of view, 

 may make all the difference in accounting for the 

 undoubted illuminating power of the gas. There are 

 other important differences between the analyses, 

 which are outside of the scope of the present paper. 



I may remark in general that the natural gas, 

 in common with the American natural gas, so 

 frequently discovered above and in association 

 with the petroleum springs, is chiefly remarkable 

 for its great heating power when mixed with a 

 large proportion of air. Its main usefulness may 

 thus be said to consist in lighting by incandescent 

 burners, for fuel in manufacturing-engines, and 

 general household purposes. 



Whatever results may accrue from these lighting 

 and heating properties, or whatever the discovery 

 may point to in a commercial direction, the fact 

 nevertheless remains that the discovery is a sub- 

 ject both interesting and instructive, and, I think, 

 worthy of consideration. 

 Uckfield, Sussex. 



THE ACETYLENE EXHIBITION. 



/CONSIDERING that it is only about four years 

 ^-^ since M. Moissan first discovered the present 

 process of making carbide of calcium in an electric 

 furnace, we may describe the exhibition now being 

 held at the Imperial Institute, South Kensington, 

 as a success. Carbide of calcium is the basis of 

 acetylene gas. It has been interesting to watch 

 the progress of invention in connection with the 

 acetylene gas industry. Mechanics have in many 

 instances set science at defiance, and consequently 

 in such cases the failure has been great.- Still, the 

 exhibition of apparatus for making the gas and 

 lamps for burning it makes a brave show when 

 it is fully alight at South Kensington, as such 

 failures have been weeded out. 



It would be difficult to find any place so perfectly 

 illuminated, as the gallery at the Institute, which is 

 lit by acetylene. It produces a brilliant but not 



harsh effect, and colours fugitive by other artificial 

 lights appear as in daylight ; so the pictures 

 adorning the rooms specially prepared to exhibit 

 them by acetylene light show to the best 

 advantage. The light will be invaluable for 

 town and country naturalists on account of this 

 quality. The exhibition, although promoted by a 

 company of carbide makers, is to a large extent 

 under the auspices of the Society of Arts and the 

 Executive of the Imperial Institute. A committee 

 formed for preliminarily examining the apparatus 

 before being accepted was appointed by the Society 

 of Arts, which decided on certain rules that appear 

 good as a whole, when we are reminded of their 

 lack of precedent. This committee included Major- 

 General Sir Owen Tudor Burne, K.C.S.I., Sir 

 Frederick Bramwell, Bart., D.C.L., F.R.S., Prof. 

 James Dewar, LL.D., F.R.S., Mr. Harry Jones, 

 M. Inst. C.E., Prof. Vivian Lewes, F.I.C., Mr. 

 Boverton Redwood, F.R.S.E., Prof. W. C. Roberts- 

 Austin, C.B., F.R.S., Prof. J. M. Thompson, F.R.S., 

 and Sir Henry Trueman Wood, the Secretary of 

 the Society of Arts. It is said that a rigid examina- 

 tion was made, under the direction of those gentle- 

 men, of all apparatus sent in for exhibition, and 

 several proposed exhibits were rejected. It is not 

 easy to say how many exhibits are at present on 

 view, as we understand the catalogue has not been 

 issued. There are, however, about a couple of 

 dozen generators of different types, making the gas 

 for as many chandeliers. In the north gallery 

 are also numerous stands of exhibits showing the 

 various forms of generators and lamps. 



With regard to the generators, there are three 

 systems at work : (i) those in which the gas is 

 generated by water being allowed to drip, or flow 

 in a small stream, on to the top of the carbide ; (2) 

 those in which water rises around the carbide ; 

 (3) those in which the carbide falls into the water. 

 An examination of the exhibits shows that the 

 former system has been hitherto chiefly adopted 

 by the inventors. This system is certainly the 

 most easily manipulated in designing either a 

 generator or a lamp, and has naturally, therefore, 

 been followed. We have it, however, on the 

 authority of Professor Vivian B, Lewes, who has 

 studied the question, that the safer method is the 

 plunging of carbide direct into the water. We 

 purposely, at this stage, refrain from especially 

 noticing any particular exhibit, as all are being 

 tested under the direction of the committee above 

 referred to. In due course a report is to be 

 issued with reference to the exhibits. Acetylene 

 illumination is " in- its infancy," as we used to 

 say of electricity, and will doubtless be perfected 

 very rapidly, as it is already an irresistible com- 

 petitor to both electric and coal-gas lights. The 

 exhibition is well worth visiting, especially as being 

 the first of its character in Britain. 



