TRANSACTIONS OF THE SECTIONS. 39 



of sand upon the skin, as to the presence of sulphur iind sulphuretted hydrogai in the 

 muds. 



An Account of Apparatus and Processes for tJie Chemical and Photometrical 



Testing of Ilium itmtinf) Gas. By Professor W. B. IIogers. 

 Professor Kogers stated that the instruments and processes, of which he pro- 

 posed to give a shoii; account, had been devised and employed by him as part of 

 the system of gas inspection which lie had organized for the State of Massachusetts, 

 and which applied to the mechanical measurement as well as to the photometric 

 and chemical testing of illuminating gas. 



1. The entire plan comprises the primary determination of the cubic foot, 

 standard measure, and its convenient adjustment for use in gauging the gaso- 

 meters employed in meter-testing in different parts of the State. This differs 

 chiefly from the apparatus in use iu Great Britain in being moveably suspended, 

 and expelling the measured volume of air by its descent in a tank, the final 

 reading on the gasometer being taken, after adjusting to zero of pressm-e, by a 

 pressui-e-gauge of extreme delicacy. Figm-es of the standard appai-atus and the 

 pressure-gauge were exhibited to the Section. 



2. To give gi'eater facility and certainty to the obser\'ations on the registra- 

 tion of meters, two contrivances were adopted, the one intended for a ready 

 and secure adjustment of the connexions at the inlet and the outlet of the meter, 

 and the other for indicating the temperature and the pressure of the air or gas at 

 these points. The former apparatus consists of a clamp com2)osed of two metallic 

 limbs, hung b\' pivots on a central piece, and capable of being fixed at any required 

 degree of opening by the action of a screw passing through the central piece. 

 When thus firmly attached to the naiTow or wide neck of the meter, as the 

 case might be, the clamp is used as a gallows-screw, by having a second screw 

 working within the screw of the clamp-head already described, which is made 

 to bear upon the end of the connecting tube, so as to make the junctiu^e imfail- 

 ingly tight. 



■ The other contrivance to be applied to the meter, in observing its registration, 

 is a short horizontal connecting tube, whose opening at one end is in a flat surface 

 at the lower side, capable of being secured by the apparatus just described upon 

 the inlet or outlet of the meter. Near this end the tube enlarges to a little chamber, 

 in which is inserted the small cylindrical bulb of a delicate thermometer and one 

 end of a siphon-gauge, so as to enable the observer to read the temperature of the 

 entering and issuing air, and to determine its ])ressiire, or to test the meter for 

 leakage. On the outlet side, this appendage is prolonged by a short rubber-tube, 

 which can be closed by a clip at the moment of completing the registration. And 

 the outer end of this tube is Im-nished with a disk-stopper, which, by turning more 

 or less, varies the apertiu-e to secure the proper rate of transit of the air or gas. 



3. For the chemical testing of gas, Professor liogers devised a form of simple 

 eudiometer, which has been found to answer the pur]^)ose better than those usually 

 employed in gas inspection, both on the ground of convenience and accuracy. It 

 consists of a tube with a cylindrical enlargement at the closed end, the tube being 

 graduated to xa^o^ths and tenths of troths of the entire capacity. This at its open 

 end is fitted -nath a hollow stopper accurately ground, and intended to hold the 

 several liquid absorbents used in the successive expeiiments. The entire tube, vnth 

 enlargement, is enclosed in a water-case, consisting of a slender cylindrical vessel of 

 glass filled vnt\i water at the teniperatiu-e of the room, the open mouth of the tube 

 projecting slightly from the cork-stopper of the case. Through the gi-eat specific 

 heat of water, it is found that the temperature of the gas, while submitted to 

 successive testings, is almost completely protected from the effect of the necessary 

 handling of the apparatus. 



With this eudiometer it is quite easy to determine, first, the percentage of 

 carbonic acid in the gas, then the illuminating hydrocarbons, and then the 

 oxygen and the carbonic oxide, by introducing in the hollow stopper the appro- 

 priate reagents. The hydrogen and light carburetted hydrogen may be sub- 

 sequently detei-mined by explosion of the residue with oxygen, in an" apparatus 

 consisting mainly of two glass tubes, united below by a long loop of rubber-tube, 



