THE TIDES 



303 



iervations. Instruments for measuring and recording the 

 height of the water at any time give us results of observa- 



FIG. 129 Tide Gauge 



tions. 1 Here is such an instrument a tide gauge (Fie. 



1 The various instruments and tide-curves referred to in this lecture 

 are fully described and illustrated in a paper on " The Tide Gauge, Tidal 

 Harmonic Analyser, and Tide Predicter," read before the Institution of 

 Civil Engineers, on ist March, 1881, and published in their Proceedings 

 for that date. 



