328 



REPORT — 1889. 



similar lateral configuration is affected by the horizontal and vertical 

 dimensions, and the relation which these bear to one another and to the 

 tide period so as to place the laws of similarity on which the practical 

 applications of the method depend, on as firm an experimental basis as 

 possible. 



It was suggested provisionally that two working tanks should be 

 constructed, one as large as the circumstances of the laboratory would 

 admit, and one of half the linear dimensions of the larger tank. Professor 

 Reynolds was empowered to appoint an assistant to make the necessary 

 observations. 



At a second Committee meeting, held at Owens College, Manchester, the 

 models constructed were examined, and it was arranged that Professor 

 Reynolds should draw up a report on the results so far obtained. 



On Model Estuaries. By Professor Osborne Reynolds, F.B.8. 



Having carefully considered and sketched out designs for the tanks 

 and appliances in accordance with the resolutions of the Committee on 

 February 6, I obtained the assistance of Mr. H. Bamford, B.Sc, from 

 Easter up to the date of the meeting at Newcastle. The working 

 drawings for the appliances were commenced immediately after Easter, 

 and the work put in hand, the experiments being commenced in each 

 tank as soon as it was ready. 



The General Design of the Appliances. — A great object in designing the 

 tanks was to make the most of the facilities in the Whitworth Engineering 

 Laboratory, Owens College, in respect of a continuously running shaft, 

 a supply of town's water and wastes, also a water supply (13,000 gallons) 

 from a storeage tank at 116 feet above the floor of the laboratory, and a 

 discharge into a similar tank below the floor, with pumping power to 

 raise the water back when required, also floor space. 



The available floor space, although very conveniently placed with 

 respect to the water and power, was strictly limited by resisting struc- 

 tures to 10 feet wide and 22 feet long. This admitted of an extreme 

 length for the larger tank of 16 feet, and an extreme width of 4' 8", leav- 

 ing 2' &' for the width of the smaller tank, the remainder of the space 

 being the least possible that would admit of access to all parts of the 

 tanks. The internal dimensions of the tanks as designed are : — 



Tank B. — Half the dimensions of A. 



The proportions of the tide-generators and fixed pans were deter- 

 mined, so that in tank A the greatest rise of tide over the whole tank 

 Bhould be 2" ; which was double the tide used in my previous experiments, 



