ON THE FLOW AND ACTION OP WATER CONTAINING SOLID MATTER. 403 



EAIN-GAUGES (continued). 



of a small pumping steam-engine, and containing mechanism for diffusing 

 solid matter of different kinds in the water. 



4. The water will be made to flow along the canal at first pure, and then 

 with different proportions of different kinds of solid matter in suspension, and 

 with different depths of current. 



5. Observations will be made of: — 



A. The declivity of the surface of the water. 



B. The velocity of the current at the surface, bottom, sides, and in- 



termediate points, also the mean velocity. 



C. The mode of motion of the particles as seen through the plate-glass 



sides of the trough. 



D. The rate at which solid matter is either deposited or swept away 



by the current under various circumstances. 



E. The temperature of the water. 



E. The direction and velocity of the wind when the trough is exposed 

 to it. 



6. Experiments to be made to determine the quantities of solid matter 

 contained in samples of water taken from different points in the length, breadth, 

 and depth of the trough. 



7. Observations and experiments to be made with the inner surface of the 

 trough roughened in various ways. 



8. Also with weirs and other obstacles of different forms and in different 

 positions. 



9. The results of the observations and experiments to be compared with 

 those of observations (so far as these have been recorded) made upon actual 

 rivers and on the great scale. 



10. The whole results to be submitted to mathematical analysis, in order to 

 deduce general laws and practical rules from them. 



11. The rough estimate of the outlay required for materials, work, and pay 

 of assistants and workmen till the next Meeting of the British Association 

 is £1500. 



This is exclusive of the pay of the engineer from the Public Works De- 



