'~0 Progress o f Civil Engineering.

shall find, after deducting 30 per cent. interest for the outlay, and making every allowance for repairs, and loss of time when the machine is not at work~ that it can excavate 957 cubic metres of earth at a cost oI 48 francs 50 cents; whereas we now pay for excavating the same quantity, 478 francs 50 cents. Iu short, tile invention of M. Gervais bids fair to make a great revolution in the mode nf excavation, and we look forward with a degree of impatience for the decision of the committee of the academy.--Inventors ~ • ~ d ~ ) o g a l e . Mining Rev.

Description of a ltlachine called a Floating Clough. By GEORGE ELLIS~ Grad. Inst. C..E.

Tile machine here described is used fi)r scouring a channel which leads from tile Winestead l)rainage and Ifaven of Pattrington~ into the river ttum- ber. It is constructed in the following manner : - -The frame is made of timbers six inches by four, twelve feet Iong~ nine wide~ and six deep. This frame is covered with planking two inches thick, and through tile middle of it a culvert is lbrmed with planks, two feet six inches in width,with a small lifting door at one end. Connected with the bottom and projecting in front are two long beams called feelers, which keep tile machine in its course, and in the Iront are fi'ames of wood shod with rough iron like the teeth of a saw, and these are connected with racks which can be raised by a lever.

At each side of the machine there is a wing which is made to fit the slope of the banks, to dress the mud from the sides, and to keep up the water be- hintl the machine.

At high tide the machine is moored in tile middle of the channel, the wings are extended and kept so by ropes, and when the tide is at half ebb the plugs are taken out, and the water rises about two feet in the machine, which causes it to sink; the plugs are replaced, and thus it remains till full. ebb, when the iron-shod frames are let down in front, and the tide forces the whole machine, which is like a great dam~ gently (Iowa the stream~ scraping with it all the mud down to the river, where it is emptied, and. floated back with the return tide, The whole distance, about three miles~ is perlormed in two hours. A machine of the same kind is used with great advantage at Great Grimsby. Proceed. Inst, Civil Et~g.

.Description of a Sawing Machine for cutting o f Bailway Bars. By JosEer~ GLYn~, M. Inst. C. E.

The advantage of having the ends of the railway bars cut as nearly~square as possibI% that they may truly abut against each other, is so grea b that many attempts have been made to effect it. The author in thiscommuni- cation describes the method which is adopted at the Butterly Works in th~ manuthcture of the rails tot' the Midland Counties Railway. In general th~ ends, rough and ragged as they come from the roils, are separately reheat- ed and cut off by tile circular saw, but the accuracy in this case depends on the workmen presenting the bar at right angles to the plane of the saw. As this cannot be insured, the difficulty may be obviated as follows. The axis of the saws and the bed of the machine, which is exactly like that o f a s[ide lathe~ are placed at right angles with tile line of the roils in which the rails are made; the saws are fixed in headstocks and slide upon the bed~ so as to adjust them for cutting the rails to the exact length~ and are thre~