of simple alimentary Substances, fyc. 37 



taining the quantity of carbonic acid gas yielded by a known 

 quantity of it ; while in the other two, the same can be readily 

 ascertained by means of the same data, and by noting the 

 excess or diminution of the original bulk of the oxygen gas 

 employed. Such are the simple and universally admitted 

 principles on which the following method of analysis is founded; 

 the only novelty in which, therefore, is the form of the appa- 

 ratus ; and of this it is hoped the following summary sketch, 

 and annexed figures, will convey every requisite information. 

 Fig. 1. Plate I. represents a front view or elevation of the 

 whole apparatus in the act of being employed. A B is a plat- 

 form, two feet square, surrounded by a ledge about 2 J inches 

 high, for preserving any mercury that may chance to fall about, 

 and furnished with four adjusting screws (of which two, C C, 

 are sectional views), by means of which it may be placed per- 

 fectly horizontal. Into this platform, in the manner repre- 

 sented, are fixed perpendicularly four square pillars, DE,DE, 

 about four feet and a half high, at the top of which is placed 

 another small platform, F F, about four inches wide, and which 

 may be fixed or removed at pleasure by means of the brass 

 pins ab, ab. II are glass tubes graduated with the utmost 

 care to hundredths of a cubic inch, and which are cemented 

 at bottom into semicircular iron tubes inclosed in the blocks 

 K K (as represented by the dotted lines). These iron tubes 

 project a little below the wood at the lower part, where they 

 are furnished with iron stop-cocks, S S, for drawing off the 

 mercury when it may be necessary. Into the other end of these 

 semicircular tubes are likewise cemented the glass tubes L L 

 (of smaller dimensions, and a little longer than the tubes 1 1), 

 and forming with them, when taken together, inverted syphons. 

 The r smaller tubes, L L, are represented as surmounted by fun- 

 nels, R R, furnished with stop-cocks, the object of which is to 

 permit the mercury to flow into them with any velocity that 

 may be required. On the tops of the larger tubes, 1 1, are ce- 

 mented the vertical stop-cocks, M M, of which fig. 2. Plate II. 

 is a sectional view on a larger scale, and which renders the 

 construction so obvious, that perhaps no further remark is 

 necessary, than merely stating that the cup, a, is filled with 

 oil, and that the plug, b, which is square at the upper part, 

 and adapted to a key, is furnished with a shoulder, on which 

 the screw-cap, c, rests, and by means of which it may be 

 tightened at pleasure*. On 



* These syphons are fixed together independently of the general 

 frame-work, and may be removed at pleasure by taking out the pins 

 c d, cd, and ef, ef. This admits of their being replaced by others of 

 different sizes. Those of a larger size have balls near the top, as repre- 

 sented 



