CLAYS OF NEW YOBK 633 



100 to 300 feet. Within these limits it is economical to use one 

 horse carts, but above 300 or 400 feet there are other means of haul- 

 age which will generally be found cheaper. There are exceptions 

 where carts are used for hauling long distances; for instance, at 

 Port Ewen on the Hudson the clay is carted 900 feet in some 

 cases, and at Haverstraw some of the firms bring their clay a dis- 

 tance of a quarter of a mile in one horse carts. The character of 

 the Hudson valley clay banks is such that train haulage would not 

 be practicable, as the tracks would, have to be shifted so often. 



Cars. As a rule where the haulage distance exceeds 500 feet 

 cars are used. They are run on tracks and drawn by horses; if 

 possible the track is laid down grade from the bank to the yard. 

 Sometimes the loaded cars are run down to the yard by gravity, 

 the horses being only required to draw them back when empty. 

 Cost 10c a cubic yard for about 500' feet lead. 



Locomotive haulage. This is a cheap method where the scale of 

 operations warrants it; that is to say, for a yard having an annual 

 capacity of 15,000,000 or upward. The cost by this method is 

 about 5c or 7c a thousand brick (about one and a, quarter to one 

 and a half cubic yards of clay being reckoned to a thousand brick) 

 for a distance of 600 or 800 feet. It is necessary, of course, to have 

 cars filled with clay ready for the engine as soon as the empty 

 ones are drawn back;* otherwise the expense would become great if 

 the engine had to spend much time waiting. The cost given above 

 does not include wear and tear on plant. 



Wire rope haulage. A few yards use this method where the 

 haulage distance is small; the winding drum is placed under the 

 machine shed near the pug mill or crushers; side or bottom dump- 

 ing cars are used. 



Gravity planes may also be mentioned, but they are less used than 

 they might be. 



Purification of clay- 

 In the manufacture of common clay bricks it is seldom necessary 

 to give much time to the preparation of the clay, but in the case 



