20 MASSACHUSETTS HORTICULTURAL SOCIETY. 



Grades of clay used in the manufacture of flower pots are almost 

 as numerous as the banks in which they are found, and require 

 many different methods of treatment ; and to proper treatment is 

 largely due the excellence of the ware. Our bank in Cambridge 

 contains a very superior quality of clay for flower pots. Unfor- 

 tunately for us, it also contains very many small stones which must 

 be disposed of in some way before using. 



To separate the clay from the stone has always been a very 

 perplexing as well as expensive operation, and we have spent 

 many thousands of dollars to accomplish this end, and are still 

 experimenting. Three years ago we erected at our clay bank an 

 expensive factory for this express purpose, putting in machinery 

 capable of handling six hundred tons daily, which produced one 

 hundred tons of sifted clay. A short description of this process 

 may be interesting to you. 



The clay is first ploughed by means of a horse and capstan, 

 whereby one horse will do the work of twenty men with picks. 

 This clay is then loaded in dump carts and carried to the mill, 

 where it is shovelled through a disintegrator which expels the 

 larger stones and crushes the smaller ones. It then falls on an 

 endless belt and is carried to a revolving dryer. This is a new 

 western patent, wherein by the use of crude petroleum for heat, we 

 evaporate from twenty to twenty-five per cent of moisture from the 

 clay, and while it passes through a direct blaze of white heat 

 there is sufficient moisture all the time to prevent it from burning, 

 which at this stage would make it worthless. To demonstrate 

 this point beyond question, paper and dry shavings were passed 

 through with the clay, and they came out without even scorching. 



From the dryer it goes into large bins, where it must remain 

 twenty-four hours, so that portions of it which have become too 

 dry and hard may absorb the moisture from that not dry enough. 

 From these bins it is carried to whippers, which beat the clay 

 without further crushing the stone. From the whipper it goes to 

 the revolving screens, and thence to the elevators. 



The next process is mixing, or, as we term it, pugging, the clay, 

 which is all done by machinery. From one machine it comes out 

 very soft and plastic, to be worked in plaster moulds ; from the 

 other cut into hard cubes for the iron moulds of the machine. 



The pot machine and jigger of today does each the work of 

 from six to eight men at the wheel, even at as lato a date as 1885. 



