title ea, ial 
Wood’s Portable Self-Registering Tide-Gauge. 75 
hours, and is marked by divisions to astronomical time, and 
revolves so that the point of the pencil is always at true time 
on the eylinder, while its transverse motion indicates the 
height of the tide at the corresponding time, and thus de- 
scribes on the cylinder the form of the tide-wave at that 
place. The morning tides will thus cover one-half of the 
cylinder in a fortnight, and the evening tides will cover the 
other half. 
By a simple contrivance, it is proposed to move this cylin- 
der at the end of each fortnight along its axis, so as to serve 
as long as may be required, without changing the paper. 
Motion is given to the cylinder by connecting it with the 
wheels of the clock. 
January 22. 1844. 
Report by a Committee of the Royal Scottish Society of Arts on a 
Self-Registering Tide-Gauge, by John Wood, Esq., of Port 
Glasgow. 
The Committee having carefully examined this gauge, are of opinion 
that it is a simple and very ingenious invention, and well deserving of 
the favourable attention of the Society. It exhibits distinctly the rise 
and fall of the tides every day, by means of a pencil traversing back- 
wards and forwards on a sheet of paper, and tracing out a straight line 
corresponding in length to the height of the tide ; and the paper being 
wrapped round a cylinder, which advances a step forward in rotation 
each tide, a series of tides are thus represented by parallel lines, in a 
manner so as to shew very strikingly, and by regular curves, the differ- 
ent variations of the tide from day to day, and from month to month ; 
and all these curious results are obtained by the single motion of a wheel 
and axle, with chains or cords, which communicate the motion in a sim- 
ple manner, from the axle of the wheel to the traversing pencil contin- 
uously, and to the cylinder containing the paper at the interval of each 
tide. From the testimony of Mr Scott Russell, by whom the descrip- 
tion of the gauge has been drawn up, it appears that the machine is 
capable of thus registering the height of high and low water for four 
months together, without requiring any attention whatever; and at the 
end of that time it is only necessary to supply a new sheet of paper, and 
repair the pencils, to enable it to go on for four months longer. We 
have no doubt, from the specimen of work accompanying the gauge, that 
this machine is capable of acting with great regularity and precision ; 
and though not perhaps adapted to the minuter accuracy required by 
