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IMPROVED MORTAR MIXER.

The engravings herewith illustrate a new form of mixing or pugging machine for making mortar or any other similar material.  It has been designed by Mr. R.R.  Gubbins, more especially for mixing emery with agglutinating material for making emery wheels; and a machine is at work on this material in the manufactory of the Standard Emery Wheel Company, Greek Street, Soho.  The machine is shown in perspective in Fig. 1 with the side door of the mixing box let down as it is when the box is being emptied; and in Fig. 2 it is shown in transverse section.  The principle of the machine is the employment of disks fixed at an angle of about 45 deg. on shafts revolving in a mixing box, to which a slow reciprocating movement of short range is given.

[Illustration:  FIGS. 1 and 2—­IMPROVED MORTAR MIXING MACHINE.]

In our illustrations, C is a knife-edge rail, upon which run grooved wheels supporting the pugging box.  To the axle of one grooved wheel a connecting rod from crank arm, F is attached to effect the to-and-fro motion of the mixing box, B. G is the door of the box, B, hinged at H, and secured by hinged pins carrying fly nuts.  A cover and hopper and also a trap may be supplied to the box, B, for continuously feeding and discharging the material operated upon.  L, L, are the pugging blades or discs on shafts, M. The shafts, M, pass through a slot in the box, B, and the packing of these shafts is effected by the face plate sliding and bearing against the face on the standard of the machine.  P is a guide piece on the standard, against which bears and slides the piece, Q, bolted on to box, B, to support and guide the box, B, in its movement.  The forked ends of a yoke engage with the collars, S, on the shafts, M, this yoke being set by a screw so that the shafts may be easily removed.  The machine is driven from the pulleys and shaft, T, through gearing, T2 and T3, and by the Ewart’s chain on the wheel and pinion, V and U.—­The Engineer.

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[Continued from SUPPLEMENT, No. 311, page 4960.]

PRACTICAL NOTES ON PLUMBING.[1]

   [Footnote 1:  From the London Building News.]

BY P.J.  DAVIES, H.M.A.S.P., ETC.

TINNING IRON PIPES, COPPER OR BRASS-WORK, BITS, ETC.

Previously, I described the method of tinning the bit, etc., with resin; but before this work on joints can be considered complete, I find it necessary to speak of tinning the ends of iron pipes, etc., which have within the last fifty years been much used in conjunction with leaden pipes.  This is done as follows:  Take some spirits of salts (otherwise known as hydrochloric acid, muriatic acid, hydrogen chloride, HCl), in a gallipot, and put as much sheet-zinc