GASES EXISTING IN SOLUTION IN WELL-WATERS. 55 



Preliminary Repori of the Committee apiiointed for the deter mi7iation 

 of the Gases existing in Solution in Well-ioaters. By Dr. E. 

 Erankland, F.R.S., and Herbert M'LeoDj F.C.S. (Reporter, 

 Herbert M'Leod.) 



Ix consequence of the investigation being far from complete, this Eeport 

 must be considered as merely a prclimiuarj'- one ; a more detailed account of 

 the results obtained, and the inferences to be drawn from them, must be 

 postponed till a future occasion. 



The apparatus employed in these and other experiments was described at 

 the last meeting of the Chemical Society, and has been published in the 

 Journal *. 



In collecting the waters it is, of course, of the greatest importance that 

 they should be prevented from coming in contact with the air, otherwise 

 serious errors might be produced in the determination of the gases dissolved. 

 In order to avoid these errors, the tap delivering the water from the jjumps 

 is connected by means of a caoutchouc tube with a tubulure at the bottom of 

 a tin cylinder, about 10 inches high and 7 in diameter. The water is turned 

 on and allowed to flow over the edge of the vessel ; thus only the surface of 

 the water is exposed to the action of the air, and the liquid at the lower part 

 of the vessel is protected by the upward ciu'rent and continual overflow. 



The bottles used for collecting the waters hold a little more than 100 

 cubic centimetres, and a separate quantity is used for each experiment. 

 Into each bottle a piece of glass tube, bent in the form of a U, is intro- 

 duced ; one end of the tube is sealed, and in the closed limb a bubble of air 

 is confined by mercury which fills the open limb and the bend. In the col- 

 lection of each water, four of these bottles are lowered by means of pieces of 

 string into the tin vessel, while the water is flowing over its edge. After 

 being filled each bottle is carefully examined, and if any bubbles of gas 

 adhere to the sides they must be removed. The bottles are then again 

 lowered into the vessel and the temperature observed. A siphon is now 

 passed to the bottom of one of the bottles, and after it has drawn two or 

 three hundred cubic centimetres of water through the bottle, it is placed into 

 the second. The first bottle is now raised, and while its neck is still under 

 the water, a slightly greased stopper is put into the neck and carefully 

 pressed down. This force compresses the air contained in the glass tube, 

 and if the pressure is sufficient, it prevents the escape of gas from the water, 

 a precaution which in some cases is very necessary. The siphon is then 

 transferred from the second into the tlurd Isottle, and the second is closed and 

 removed. When the four bottles have been filled, the stoppers are covered 

 "with ground caps. The caps are next filled with mercury through small 

 holes at their tops, which are afterwards closed with glass stoppers. 



The gases should be removed from the waters as soon after collection as 

 possible. In the following cases, the greatest length of time which was 

 allowed to elapse between these operations was five days, but usually the 

 removal of the gases was effected the day after the collection. 



With so few results as have been obtained up to the present, it wiU be 

 impossible to do more than point out the small quantity of oxygen in the 

 waters from deep wells as compared with those from shallow ones, and with 

 rain- and river-waters. The quantity of nitrogen is also very remarkable, as 

 being in all the cases, except the river- and rain-water, in excess of the 



* Journ. Cliem. Soc, ser, 2, vol, vii. p. 307. 



