602 Report of the Trials of Ploughs, Harrows, §'c., at Hull. 
Section V. — Digging Machines, Class 31. 
One entry, namely, Comstock's Rotary Spader, No. 1252, 
manufactured and exhibited by Messrs. Porter and Co., of Lincoln. 
This implement was, we believe, first exhibited at the Bury 
Meeting in 1867, when it was submitted to trial by the Miscel- 
laneous Judges, who, however, made no award. In light soils 
the tines or diggers enter the soil readily, disturb the land to a 
considerable depth, as much as 6 or 7 inches if required, and 
leave it in a finely-pulverized condition. As we had not an 
Fig. WO.— Comstock's Botary Spader, No. 1252. 
A. Transverse bar carrying the disgers. 
B. Links at end of transverse bars forming 
endless chains. 
C. Rollers on short arm of transverse bars, 
which worlc over cams to give the necessary 
pitch to the diggers. 
D. Chain-wheel fi.\ed on main axis of machine. 
E. Main axle forming fulcrum for b<'ll-criinl£ 
F and G. 
H. Hiinil-wheel. 
I. Counter-chain. 
J. Spring seat for driver. 
K. Steerage-wheel. 
opportunity of examining this machine, we reproduce an account 
which appeared in ' Engineering ' of September 1867, and, by the 
aid of the illustration (Fig. 110), trust to convey some idea of the 
mechanism and mode of operation, which is very ingenious : — 
" The digging portion of the Spader consists of a number of forks or prongs 
fixed to a series of transverse bars, which are connected at their extremities by 
links, so as to form an endless chain. This chain is led over chain-wheels- 
