1 883. 101 Trans. N. V. Ac. Set. 



Newberry, he pointed out that the native gold of the specimens 

 was contained in the cavities left by the decomposition of 

 pyrites. 



Mr. Arthur H. Elliott read a paper, illustrated by the appara- 

 tus, on 



AN IMPROVED METHOD FOR GAS-ANALVSIS. 



(PubHshed in the Annals, 1883). 



DISCUSSION. 



Mr. G. F. KuNZ stated that, in assisting Prof. Wurtz in a series 

 of gas-analyses, they had found that the Orsat-apparatus required 

 several days for each analysis. All joints of the apparatus were 

 kept lubricated with glycerine. 



Dr. T. Egleston remarked that the Orsat-apparatus, which re- 

 sembled somewhat that of Mr. Elliott, possessed very great advan- 

 tages in making commercial analyses of gas, in the quickness and con- 

 venience of its use. It was very portable, and he had carried it up a 

 high ladder, to a vat, in a whitelead works, made there the analysis 

 of a gas, and brought it down to the ground again without any diffi- 

 culty. It was, however, expensive, and was sometimes sluggish, 

 especially in the determinations of carbonic oxide. It is, however, 

 very suitable for the commercial analyses of gases. Mr. Elliott's 

 apparatus is more suitable for the laboratory than for the works, be- 

 cause it is so very fragile. It is likely, also, to be sensitive to changes 

 of temperature, which would necessitate making corrections for the 

 variations of the volume of the gas, especially in very cold or very hot 

 weather, when it might be necessary to have the apparatus jacketed, 

 to allow sufficient time for the observations. How quickly the volume 

 of gas will change by temperature, is shown in the oscillations which 

 occur in the delicate air-thermometer, used in the Doyer apparatus. 

 The special advantage, which is very apparent i».Mr. EUiott's ap- 

 paratus, is that the efficiency of the apparatus is always at a maxi- 

 mum, since the chemicals used are always new, and are arranged 

 in such a way that they are exposed to a very large surface ; for, 

 while the surface is not as large as in the Orsat apparatus, in gen- 

 eral, either in the tube or in the gauze part of the apparatus, it is 

 amply sufficient with fresh chemicals for all practical purposes. 

 While this apparatus does not have the same relation to commercial 



