330 REPOET— 1889. 



as possible effects a complete balance in all jDarticulars. In tank B, 

 arrangements which have the same effect have been carried out in a 

 somewhat different manner, whicli will be clear from the drawings. 



The glass covering for tank A consists of eight glazed frames, eacb 

 having two panes of sheet glass 3' 10" X 10", with ^" bearing on the 

 frame all round ; the external dimensions of the frames are 4' x 2', so 

 that they are easily handled. The glass is let in flush with, the top of 

 the wood, and each pane is fixed by four small bi-ass clips screwed to the 

 frame. In this way, except for the clips, the top of tbe glass cover over 

 the pan presents a level surface. The frames over the tide generator are 

 connected with those over the pan by a hinge joint made of two strips of 

 pine hinged to each other and to the frames. 



A somewhat similar arrangement exists in tank B, except that there 

 are only four frames eacb with a single pane 2' X 2'. In both tanks the 

 glass frames are fastened by screws to the sides, which screws have to 

 be taken out before the frames can be removed. 



The gearing, which is arranged to be driven either from a small water- 

 engine or the running shafting, is shown in the drawings. 



The crank is adjustable so as to give any required tide up to the 

 maximum. In tank A, the pulley driven by the belt from the motor or 

 shaft makes 700 revolutions for one of the crank, and has a fly-wheel 

 which considerably helps the motor over any little irregularities in the 

 balance. The gearing in tank B is driven either direct from the motor 

 or from a pulley on the second shaft in the gearing of A, in which way 

 a fixed relation in speed is obtained when the tanks are working together. 

 The motor was obtained from Alderman Bailey, Albion Works, Salford ; 

 it is a double-acting oscillating water-engine with a f" piston and 4" 

 stroke. The available pressure of water is 50 lbs. steady pressure ; the 

 consumption is about 1 gallon per 100 revolutions. At the highest speed, 

 2 tides a minute, the motor only makes about 200 revolutions per minute, 

 so that the 13,000 gallons will keep it going over three days, and has 

 done so from Saturday till Tuesday, Monday being Bank Holiday. It 

 has run day and night and Sunday, since starting in June, without once 

 stopping, making over 12,000,000 revolutions, and is none the worse. 

 If it used the full pressure it would, when run at 100 revolutions, do 

 about '044 horse-power. Owing to the careful balance of the tanks and 

 the use of spur instead of worm gearing, the work required is not more 

 than '008 horse-power, so that five-sixths of the pressure is spent in ovei'- 

 coming the fluid resistance, which, increasing as the square of the speed, 

 affords a very important means of regulating the speed, which, indeed, is 

 thus rendered very regular. 



Surveying Appliances. — Since the configuration of the sand produced 

 under different circumstances can only be compared by means of records 

 such as charts or sections, the practicability of the investigation depended 

 on the finding of some means by which the sections or contour-lines on 

 the sand could be rapidly and accurately surveyed. 



The floor of the estuary was made fiat and carefully levelled, so that 

 the depth of sand at any point could be at once ascertained by sinking a 

 fine scale through it to the bottom ; and for this purpose scales were con- 

 structed of strips of sheet brass "01' broad and "01" thick. On these 

 the alternate '01' were painted white, and the intermediate spaces in the 

 first 0'"1 were painted red, in the second 0''1 black, and so on, the scales 

 being then varnished with paraffin. 



