304 KELVIN 



129). The floater is made of thin sheet copper, and is 

 suspended by a fine platinum wire. The vertical motion of 

 the floater, as the water rises and falls, is transmitted, 

 in a reduced proportion by a single pinion and wheel, 

 to this frame or marker, which carries a small marking 

 pencil. The paper on which the pencil marks the recording 

 curve, is stretched on this cylinder, which, by means of 

 the clockwork, is caused to make one revolution every 

 twenty- four hours. The leaning-tower-of-Pisa arrangement 



FIG. 130 Facsimile of weekly sheet of curves traced by Tide Gauge 



of the paper-cylinder, and the extreme simplicity of the 

 connection between marker and floater, constitute the chief 

 novelty. This tide gauge is similar to one now in actual 

 use, recording the rise and fall of the water in the River 

 Clyde, at the entrance to the Queen's Dock, Glasgow. A 

 sheet bearing the curves (Fie. 130) traced by that machine 

 during a week is exhibited. 



After the observations have been taken, the next thing 

 is to make use of them. Hitherto this has been done by 

 laborious arithmetical calculation. I hold in my hand 

 the Reports of the late Tidal Committee of the British 

 Association with the results of the harmonic analysis 

 about eight years' work carried on with great labour, 

 and by aid of successive grants from the British Associ- 

 ation. The Indian Government has continued the harmonic 

 analysis for the seaports of India. The Tide Tables for 

 Indian Ports for the Year 1882, issued under the authority 

 of the Indian Government, show this analysis as in progress 

 for the following ports, viz.: Aden, Kurrachee, Okha Point 



