r *,iXV*, ^*->i,' 



BAIRD & TATLOCK (LONDON) LTD. 



The operation is as follows : The covering being removed, the coarse material is fed in at F, and pieces as large as will go 

 in the opening can be crushed (unless of an exceptionally hard character). As the material is gradually crushed, it works down 

 to bottom of conical opening, passing under the pestle where it is pulverised. The centrifugal force carries the product to the 

 sides, where it is caught by the lugs H, which carry it to spout G, and discharge it. 



A number of these mortars have been examined that have been in daily use for four years or over, and are found to be in 

 the same condition as when sold, no wear being apparent, only the knobs on the working surfaces being ground off a trifle, thus 

 proving that it will' last a lifetime. 



The lines of the working surfaces are conscructed so that should there be any wear, they will always retain the same shape 

 a? when new, be easy to clean, and every particle of material evenly pulverised 



B 



Fig. 3- 



6191 



Fig. 4. 



The above figure illustrates the crusher and pulveriser with both handles in position, making it very easy to lift out the pestle 

 to clean the mortar. (Two brushes for cleaning are sent with every machine.) Another use for the handles in this position is 

 when crushing very hard or large pieces of material, take hold of both" handles and work backward and forward (or see-saw), which 

 will crush large pieces much easier.than with one handle, and as soon as the material is crushed sufficiently, take out extra, handle 

 and go on with the rotary motion. 



Following are two tables showing the ordinary time required to grind one pound each of common window glass and plg-iro 

 also showing the fineness of same after passing through pulveriser once. The pulverised product was then passed through 

 series of six sieves. The per cent, remaining on each is shown in the following table : 



GLASS. 



40 mesh sieve 

 60 

 80 

 loo 



120 

 140 



Amount passed through 140 



t per cent. 



4 



13 



59 



PIG-IRON. 



40 mesh sieve 

 60 

 80 

 100 ,, 



I2O ,, 



140 ,, 



Amount passed through 140 



oo per ecu 

 i 



4i 

 9i 

 67 



Total . . . . . . I0 o Total . . . . . . 100 



Time of pulverising . . . . . . 7^ min. Time of pulverising . . . . . . iz min. 



These tables are exact, and can be substantiated in every respect. The substances were selected on account of their common- 

 ness, and the difficulty of pulverising them is well known. 



Taking into consideration their hardness, it will be readily seen with what ease ores, rocks, clays, and other substances can 

 be pulverised to any degree of fineness with our No. i crusher and pulveriser. 



Showing rotating pestle lifted out and set on stand ready for cleaning. 



A wooden stand as shown in cut will be found very useful and convenient. It is simple, and can be made by any carpenter. 



When placed on stand the edge of the pestle should overlap the edge of the shell, so any material remaining on the pestle 

 can be brushed off into the shell and then through the outlet. 



INSTRUCTIONS. 



The material to be pulverised must be dry, and should be broken in pieces about the size of a person's thumb; the harder 

 the material the finer it should be broken. 



OPERATIKG. Put proper amount of material, according to its hardness, into the hopper, then adjust both handles and work 

 them back and forth (or see-saw), as by so doing you will get greater power, continue this until the larger pieces are crushed, 

 then remove one handle and go on with the regular rotatory motion, same as turning a coffee mill, until the material has nearly all 

 passed out of the hopper, then put in another charge and repeat the operation. 



It is customary with a great many users to return the material to the hopper a second time, and repeat the pulverising process, 

 and then not use a sieve. 





14 CROSS STREET HATTCTN GARDEN, E- C 



