1817 32 FOND OF MECHANICS. 29 



every spare hour, and the Saturdays, he devoted to searching for 

 bones of every kind of animal, all of which he brought home, 

 and had carefully cleaned and classified. One day he brought 

 the entire skeleton of an infant, which he had got from some 

 surgeon. He was determined to be a doctor ; but considering 

 that in a large city the study and profession of a single organ 

 was as much as one man could undertake, his aim was to re- 

 strict himself to the study of the eye or the ear. That of the 

 eye had special charms. These facts Mr. Dick vividly recalls 

 as connected with his visits to Edinburgh. The letter is not 

 dated, but it is probably of 1830. 



" DEAK SIR, Since we parted, I have been very busy with 

 French, Greek, and Latin, but the vacation has freed me from 

 these. The Society has been recommenced, and we have very 

 warm debates on various subjects. Daniel still conducts the 

 Journal, which has had its pages filled with original communi- 

 cations on various subjects. A communication of any kind 

 would greatly enrich the Journal If you would send us an 

 account of the power you had saved in a threshing-mill. The 

 ground 1 railway between Edinburgh and Dalkeith is now com- 

 pleted, and coal is sold from the depot. I visited it a few weeks 

 ago. The carts are drawn by horses all the road, except a space 

 something more than a mile up an inclined plane through the 

 tunnel, up which they are dragged by a fixed steam-engine. 

 The piston puts in motion two drum cylinders, on which the 

 ropes are coiled. The ropes rest on large cast-iron wheels or 

 pulleys. The tunnel is about three-quarters of a mile in length. 

 There is another large steamboat, called the ' Eoyal William' 

 (in honour of our king), of 200 horse-power, going between 

 Leith and London. There is a curious property relative to in- 

 clined planes, i.e., of bodies which of their own accord ascend 

 inclined planes, and, contrary to the laws of gravitation, will 

 not descend, but, though forced down, will ascend, and remain 

 at the top. The figure of this body is two equal cones, joined 



1 Mr. Dick was at this time zealously occupied with an ingenious invention of his 

 own, a system of suspension railways, which he had patented, and of which his young 

 friends Aveve zealous partisans. Hence the term "ground railway." 



