221 



From the above statement it is apparent, that considerable 

 improvements have been made on the machine, since the 

 time of Brown, and from the rude delineation of it as intro- 

 duced into Ireland, about threescore years since, by his in- 

 genious pupil Robertson.* Some persons approve of the 

 uniform use of the third wheel, within 2i or 3 F. of the point 

 of the pole : but that cannot be necessary, as already men- 

 tioned, but with subjects of extraordinary length or weight ; 

 and it is quite inadmissible in any case, in this position, unless 

 where the tops have been severely lightened or mutilated. 

 Others, in some of the northern districts of this kingdom, 

 where both the soil and climate are extremely propitious, 

 have added what they denominate a " heel-beam," 1 8 In. 

 out from the axle or crossbar. But, as it appears, this should 

 much rather have been called a fore-beam, as it is placed 

 immediately in front of the axle, and next to the draughtbar, 

 to which the horses are put. In other words, the side-stays 

 are lengthened out, making them between 7 and 8 F. long, 

 by which means they must often interfere with low-spreading 

 branches ; and the position of the axle being altered, it 

 causes the frame to project about 18 In. beyond it. A 

 machine so constructed they call an " Alleviator ;" but on 

 what principle or analogy, does not appear very evident. Of 

 this sort of machine I have no experience : but I cannot per- 

 ceive any good reason for making such a change so near the 

 centre of gravity, which must always be in the axle ; as it 

 seems apparent, that in practice it must make the tree more 

 difficult to be drawn down, and more troublesome to be 

 balanced during the transportation, thus multiplying, instead 

 of " alleviating" the planter's difficulties. 



* See Hayes's Treatise on Planting, and the Management of Woods, 

 p. 42 — 47. Also Sect. II. anteh. 



