ON THE RESISTANCE OF WATER. 149 



" 3. Model A to be in two parts, joined at the circular midship section, so 

 that by turning the after-body through a right angle about a longitudinal 

 axis the water-hnes can be converted into buttock-lines, and vice versa. 



" 4. Experiments to be made according to the method formerly put in prac- 

 tice by Mr. Scott Russell, in which the uniformity of the propelling force is 

 maintained by means of a regulating weight hanging from a pulley, under 

 which the hauling cord passes ; the model to be guided in a straight course 

 by means of a stretched wire. 



" 5. Those experiments to be made principally at speeds not exceeding the 

 natural speed of the wave corresponding to the length of the model, viz. 

 about two knots per hour, or 3-38 feet per second; but a few experiments 

 may be made at higher speeds. 



" 6. The experiments to be made on each model under two circumstances, 

 viz., with the model immersed as nearly as may be to the middle water-line, 

 and with the model totally immersed." 



The programme of experiments having been thus drawn up by the Com- 

 mittee, the superintendence of its execution was undertaken by Mr. Scott 

 Eussell, as being the only member of the Committee resident in or near 

 London. 



Full-sized drawings of the models having been prepared in conformity 

 with the programme, the models were made from those drawings*. 



The actual execution of the experiments was entrusted by Mr. Russell to 

 Mr. J. Quant, Naval Architect, who performed that duty with a skill and 

 assiduity which the Committee desire to acknowledge in the highest terms. 



The experiments were made upon a lake in Blackheath Park, the use of 

 which for that purpose was liberally granted by Dr. Joseph Kidd. 



A platform was laid down near the water's edge, and on it was erected 

 a trestle ; in the crosspiece at the top, two brass wheels were made to 

 turn in sheave-holes ; on the outside and against the platform in the water 

 an oak pole was fixed, on which pole, a little above the water, another brass 

 wheel was made to turn, care being taken that the inside of the rim of this 

 wheel was in a perpendicular line with the outer rim of the outer wheel 

 in the top of the crosspiece ; from the oak pole to a length of about 98 

 feet, where another pole was fix;ed in the water, was stretched a wire, 

 about 9 inches above the surface of the water, to act as guide for the model 

 when running, two forks being fixed on the model for that purpose. At a 

 distance of 20 feet from the outer pole was driven a stake into the bed of the 

 lake, exposing its top above the water ; at 25 feet from the fii'st stake, a 

 second was driven, and at 25 feet from the second, a third. In commencing 

 an experiment, a silk cord was passed over the wheels, and, when geared 

 round the lower wheel, the end was fixed by a hook to the model. The 

 model was then drawn, by means of another cord, to the outer pole ; and on 

 its arrival there this cord was unhooked, and the model held by a boy seated 

 on the top of the pole. The propelling weight was then suspended between 

 the two top wheels in the trestle on the platform, by means of a pulley 

 under which the cord passed ; and whilst the boy yet held the model, the 

 propelling weight was hoisted up to a height of 6 feet fi-om the ground. The 

 word " go " was then given, the model set free, and the propelling weight 

 allowed to fall to within a few inches of the ground, and there held by 

 steadUy hauling in the cord till the model arrived at the platform. While 

 the model was running, observations were taken as to the time when it 



* Both drawings were exhibited at the Birmingham Meeting and also Model B. Model 

 A, being in use, was not sent to Birmingham. 



