Popular Science Monthly 



831 



This slides along the bottom 

 of the trench and supports 

 the rear end of the wheel 

 frame work. Depth of dig- 

 ging is controlled by raising 

 or lowering the front end of 

 this framework, the rear por- 

 tion of course riding along 

 on the "shoe" according to 

 the depth of the front end. 

 A special feature of this 

 "shoe" is that a man can ride 

 on it laying tile or pipe as fast 

 as the digging progresses. 



Many widths and depths 

 of trenches can be cut by the 

 machines. Some have been 

 made six feet wide and fif- 

 teen feet deep. One machine 

 dug two hundred rods of 

 eleven and one-half inch 

 trench thirty inches deep in 

 a ten-hour day, and another 

 dug a thousand feet of 

 twenty-inch trench five and 

 one-half feet deep in the same 

 time. Small boulders, tree 

 roots, and similar barriers 

 offer no great obstruction, 

 and the machines accomplish 

 work under difficult circum- 

 stances with a celerity that 

 prising. 



Various modifications of the chain- 

 type and wheel-type have been made to 

 fit special conditions. These relate 

 largely to the shape of buckets used, since 

 digging an open trench in sandy soil re- 

 quires a far different kind of bucket than 



"Caterpillar" wheels enable the big machine to travel 

 over soft ground 



IS sur- 



making a clean-cut channel in hard clay. 

 To enable the machines to travel o\er 

 wet, soft ground "caterpillar" wheels are 

 used. 



Traveling by Parcel Post 

 'T^HOUGH our parcel post " 



IS a 

 enabling us to 



won- 

 send 



In a ten-hour day this machine will do 

 the work of two hundred men 



derful system, 

 all kinds of strange things by mail, the 

 English system can do one thing which 

 we have, as yet, not attemped. 



An Englishman who was in a hurry to 

 reach a part of London with which he 

 was unfamiliar, called at the general post 

 oflice to consult a directory. Upon ex- 

 plaining his case, the clerk gave him the 

 starlHng information that he could go by 

 parcel post for the payment of threepence 

 a mile. 



He was accordingly placed in charge 

 of a messenger who took him to his des- 

 tination. The boy carried a printed slip 

 on which was written "Article required 

 to be delived" with a description of the 

 parcel following. 



