708 KEPORT — 1878. 



Louses, until some permanent indestructible light-producing points very different 

 from the present carbon sticks be discovered. 



Nor should the sanitary advantages of electric illumination in buildings over 

 that by gas be overlooked. 



6. On a Process for Cutting through Sand-bars in Rivers and Harbour 

 Entrances. By C. Bergeron, G.E. 



The process requires the prolongation of one of the piers or jetties at the end of 

 which the sand-bar is formed. The new pier is to be made on iron piles, in the same 

 style as the numerous jetties or piers at watering places, such as Brighton, South- 

 port, Llandudno, &c. They offer no resistance either to the waves or to the currents 

 of the sea. 



The pier is to support a pipe of 8 or 10 inches diameter, into which water, coming 

 from pumping-engines on the shore, is forced at a pressure of 10, 20, 40, even 50 

 atmospheres. The pressure is in proportion of the resistance of the sand or shingle 

 of which the bar is formed. 



At every forty metres there is a branch pipe which carries down the water to 

 another pipe of the same length of forty metres. This pipe is to be put horizon- 

 tally between the piles of the pier and supported by them. 



That horizontal pipe, which is at the level of the water at low tide, and which 

 it is easy to reach every fortnight at the epoch of spring tides, has twenty outlets 

 of one inch diameter at two feet distance from each other. 



India-rubber flexible pipes of a sufficient length are tied to those twenty out- 

 lets ; they are exactly like tire-engine hose ; they are tied two and two to a plank 

 lying at the bottom, which forces the jet of water to strike the sand at a con- 

 venient acute angle. 



The jetties are prolonged as far as the total length or width of the sand-bar. 

 When the cross-section of the sand-bar has been properly measured, the highest 

 parts, which correspond to a certain section of the feeding pipe on the jetty, are 

 removed by the jets of water of that section, working only during a few minutes. 



Every sectional pipe is connected with the main feeding longitudinal pipe by 

 means of a valve. It is only four inches in side diameter, which is quite sufficient 

 to feed twenty india-rubber flexible pipes of four-fifths of an inch diameter. The 

 valves are to be opened one after the other. 



The operation of cutting the sand-bar must take place at the moment of high 

 tide, when the tide begins to recede. It is at that moment that the current of the 

 flood tide is most rapid, and when all the water accumulated in the harbours or 

 rivers begins to run into the sea. At that moment, all the sand removed by the 

 jets of water is carried away. A very larue ditch or furrow is formed at the end 

 of the jets of water, and ships are no longer prevented entering the harbour. 



