1S78.] 



Observations in the Gulf of Catch. 



35 



The self-registering tide-gauge was carefully so placed that the band 

 allowed the float to be 3 inches from one side of the cylinder, while it was 

 the same distance itself from the other side. The instrument having been 

 carefully levelled by wedges, the trestle was secured with screws to the 

 floor ; a hole was cut in the floor and a small box let down (properly fitted 

 so as to allow no sand to come in), in order that the counterpoise weight 

 might be able to act for the entire range of the instrument. 



The float band was made 35 feet 6 inches long and 33 feet of chain 

 was added to this, and fixed at its other end to the hook under the float, 

 forming a continuous band as it were. The scale of wheels adopted here 

 was i ; the barrel being 5 feet long, that scale was the largest that could be 

 used for a 14-90 feet range of tide. The float had a swivel to which the 

 band was attached, and the band also passed through two guides fixed to an 

 upright scale on one side, and through another guide fixed to the trestle on 

 the other. 



The temporary tide-gauge, consisting of a pile firmly imbedded in the 

 sand and standing about 8 feet out of the ground, was placed about the 



