116 CHEMICAL MANURES. 



extraction of superphosphate as well as to manures, or analogous 

 chemical products. Summing up, the inventors claim : — 



(1) An arrangement for the mechanical shifting of superphosphate 

 consisting of a vertical shaft o, mounted on a horizontal axis h, 

 and driven with a simultaneous movement of rotation and trans- 

 lation of which the blade r comprises projecting teeth q, prefer- 

 ably incurved on the axis, with the object of first of all bringing the- 

 teeth in contact with the material so as to commence the attack 

 of the material by the teeth, and finish it by the blade. 



(2) A method of applying the arrangement described in (1), in 

 which the horizontal shaft h of the knife, comprising a radial arm 

 p, fitted w4th a shovel s, is supported at its two extremities and 

 forms part of a screw shaft i, engaging into a fixed screw j, and 

 gearing with a driving cog-wheel A-, in which it can glide so as to- 

 avoid any false working. 



Allegri's Plant for Shifting Superphosphate from the ''Dens ". — 

 Allegri, the engineer of the united factories of the Italian agricul- 

 turists, has also patented a machine to replace manual labour in. 

 shifting superphosphate from the mixing "dens ". His appliance- 

 consists essentially of a sort of plough, to which a horizontal and 

 vertical motion is imparted. This plough traverses the chamber in 

 the direction of its length, and at each passage it detaches a small 

 slice of superphosphate and discharges it through the door in the 

 top of the chamber into a conveyor of some sort. A single work- 

 man can overlook several of these machines. This machine shifts- 

 10 tons of superphosphate an hour. The force necessary is 4 H.P. 

 The cost of upkeep is limited to changing the plough from time to- 

 time, which is the only part exposed to contact with the superphos- 

 phate. The appliance maybe fitted to any existing "den" with 

 a few alterations. 



Another method of shifting superphosphate " dens " is comprised 

 in British patent No. 20,446 (25 Feb., 1907). It consists in 

 shifting the superphosphate by a movable platform, on which it 

 rests so as to expose sides and top, so that the mass can be 

 broken up in the open air. With this end in view the floor of 

 the decomposing " den " is mounted on wheels ; in this way it may 

 be drawn out of the " den " by appropriate mechanism through a 

 movable door made in one of its sides. The superphosphate shifted 

 out of the *' dens " is then broken up by any mechanical arrangement 

 and charged into conveyors to be conducted to the drying machine^ 

 Finally, the following arrangement of the superphosphate " dens, ' in 

 a Bordeaux factory, is described, as an interesting improvement. 

 The new " dens " consist of long channels in a mass of masonrv work 

 below the mixer. These channels are 1*6 to 1*8 metres above the 

 floor of the factory. A metallic cradle placed inside these channels, 

 of which it assumes the form (naturally !), is propelled by a winck 



