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1815.] On the Analysis of Organic Substances. 273 
and in this state they will dissolve, and retain water with great ob- 
stinacy. The mode, therefore, adopted by Berzelius was probably 
inadequate to separate the whole of the water formed and this may 
account for the small quantity obtained by him on burning oxalic 
acid. The remark, however, if founded in truth, applies equally 
to all the substances analysed by him. In a quaternary compound, 
carbon and azote are perhaps the elements whose quantities we can 
most easily arrive at a just knowledge of. 
ARTICLE DV eile 
Description of an Instrument to measure and register the Rise and 
Fall of the Tide throughout the whole Flow and Ebb. By Col. 
_ Beautoy. : 
Tue parts of this instrument which are devoted to measuring the 
height of the water consists of a copper tube placed in the water of 
the sea or river in a vertical position, and provided with a float nearly 
filling its bore, at the same time that it is freely at liberty to rise and 
fall upon the surface of the water, which is admitted into the lower 
end of the tube by asmall opening, or by a pipe, and will therefore 
preserve the same level as the external water of the sea or river, and 
prevent the float being affected by the undulations of the water. 
A small line is attached to the float, and carried up to a wheel or 
roller, round which it makes several turns; and the line of a balance 
weight, being rapped pon the axis of the wheel on the opposite 
side of the centre, will cause the wheel to turn one way or other as 
the float rises or falls upon the surface of the water in the tube. 
This motion is communicated by wheel-work to a second wheel or 
cylinder, upon the surface of which a sheet of paper is fastened. 
The registering part of the instrument is an eight-day pendulum 
clock, which at every ten minutes lets fall a small hammer to make 
a mark on the sheet of paper wrapped upon the cylinder; in conse- 
quence, this sheet will be covered with a succession of marks, and 
the intervals between them will show on a reduced scale the quantity 
of rise or fall othe water during the interval, ten minutes, which has 
elapsed between the different marks made by the clock. 
The general action of the machine being understood, the detail of its 
construction will be explained by the drawing, in which Pl. XX XIX. 
fig. 2, representsthe whole machine mounted upon a tripod A A sup- 
ed upon three feet screws a a, by means of which it can be so 
adjusted that the clock will beat correctly, or in other words, that the 
escape of the teeth of the swing-wheel will take place at equal dis- 
tances from the perpendicular on the opposite sides ; the tripod sup- 
ports a mahogany table B, which is represented on a larger scale in 
+ ame 3 and 4, the first being aside view, and the other a front view, 
pon this table are erected standards C D & for the support of the 
Vou. VI, N° IV. . 
