AGRICULTURAL MECHANICS AND RURAL ECONOMY. 



53 



consist — 1st. In the greater security and strength of the walls locked and bound together by 

 this device; 2d. The bricklayer is enabled to lay several courses without the use of the line, 

 and with much greater rapidity and accuracy than with common brick, it being scarcely pos- 

 sible to go wrong ; and 3d. The spaces for mortar between the bricks are necessarily uniform, 



exact, and equal." 



Fig. 5. 



Fig. 6. 



These bricks united together form a continuous chain, very suitable for the construction 

 of domes and other such structures, as they are well adapted for resisting outward thrust, 

 and they can be united by any " bend" which is possible for common brick. The wall cannot 

 separate while there is sufficient weight on the top to keep the spurs in their channels. Such 

 bricks will be good for building deep shafts in mines. They may be also used for drainage, 

 the spaces between the courses affording a free passage for water. 



Papier-Mache Huts. 



A papier-mache manufacturer in England has submitted to the authorities a model hut 

 of that material, intended for camp use. The papier-mache pulp is mixed with rags, the 

 result of which is a paper plank much stronger than wood, all but inflammable, a non- 

 conductor of heat or cold, and impenetrable by wet. 



Boring for Artesian Wells. 



The following is a notice of some recent improvements in the machinery for boring Arte- 

 sian wells, effected by Mr. Kind, of Saxony : 



" The first improvement by Mr. Kind is what he terms the free-fall apparatus, the object 

 being to release the chisel at any moment from the rods, and by allowing its free fall to do its 

 work at the bottom of the bore-hole. This apparatus consists of a pair of tongs, capable of 

 laying hold of a bar of iron in which the chisel is fixed ; and these tongs open and shut by 

 means of the action of the water in the hole on a disc of leather during the up-and-down motion 

 of the rods. The operation proceeds as follows: — The rods, to the lower end of which the 

 free-fall apparatus and chisel are attached, are lifted to the height requisite for the subsequent 

 fall of the chisel ; during this upward motion, the water in the bore-hole presses against the 

 upper side of the leather disc by reason of the resistance it meets with by being drawn 

 through the water ; but the moment the motion of the rods is attempted to be reversed or 

 lowered, the pressure of the water against this disc is also reversed, causing it to slide a little 

 way on the rods. This motton of the disc is made to effect the opening of the tongs holding 

 the end of the chisel, which is then disengaged, and free to fall without the rods and free-fall 



