On Dr. Car twrig /it's Pedo-motive Machine. 59 



When it is necessary to remove meat for use, it can be taken 

 out of the vessel without allowing it to come in contact with the 

 oil. By pouring in water, the oil will ascend and will flow over 

 the edge of the vessel containing the meat into one placed under- 

 neath to receive it; tlms the meat can be easily removed, and 

 the oil will not be wasted. Fresh water can be })reserved in like 

 manner in situations where it is scarce, by covering its surface 

 with oil, and by putting bright pieces of iron in it. 



London, July 6, 1819. 



XI. On Dr. Cartwright's Pedo-motive Machine. By Mr. 

 Henry Meikle. 



To Mr. Tilloch. 



D London, July 5, 1819. 



r. Cartwright, in giving an account of his inven- 

 tion, in your last Number, says " that it seems nothing less 

 than a miracle, that the idea did not occur to the common knife- 

 grinder centuries ago." If I do not mistake the thing altogether, 

 Hardie's walking- crane is nothing else than the same principle 

 brought to great perfection; and if I rightly remember, there is 

 in the EncyclopcBdia Briiannica a description with an engraving 

 of a carriage moved with ratchet-wheels and treddles, which I 

 conceive to be precisely on the same principle as that proposed by 

 the Doctor at the bottom of page 425. However, as the account 

 which Dr.C. gives of his invention is very concise, he himself 

 can best explain his meaning if I have ;:;isconstrued it. 

 I am, sir, 



Your most obedient servant, 



Henry Meikle. 



*^* In laving the above observations of our correspondent 

 Mr. Meikle before our readers, we beg to ofi'er one remark. The 

 idea of working a wheel-carriage by means of ratcliet-wheels 

 moved bv treddles is not new ; but we have no recollection of 

 having before seen any j)ro])()sal for applying the whole muscular 

 strength of a man's body, by means of straps over his shoulders, 

 to the working of the treddles. This is what we consider as the 

 principal novelty in Dr. Cartwright's suggestion, and that which 

 alone gives it value as an improvement. If the strap or any 

 fixed point of resistance for the man's shoulders, while his feet 

 are employed to conmiunicate his |}owcr, has been before in use, 

 the Doctor's improvement is not new. — Edit. 



XII. Oh- 



