120 



On A[)r'icul lured Mechanics. 



The characteristic feature of this implement, however, is the form of 

 its teeth (see annexed figure). This form is calculated to hinder 



S§H> 



[Finlaysoirs Patent Harrow.] 



clogging. Earth full of couch or other weeds coming against it will not 

 stop there, but will rise over the tooth, and fall down on either side, the 

 earth below and the weeds above, on the surface of the land. 'J'he faults 

 of this machine are three : 1st. The wheels are always made too small, 

 and the frame is too near the ground, so that in working rough land 

 this clogging takes place in spite of the excellent form of the teeth. 

 2ndly. The clogging takes place also from another cause. It will be 

 seen that the distance between any two adjacent teeth, according to the 

 arrangement in this machine, is only double of the distance between the 

 paths of the teeth — only 1 foot. Rough, cloddy, and couchy ground will 

 thus soon stop the machine. This may be remedied by a different 

 arrangement, as that in the annexed figure for instance, where the dis- 

 tance between any two teeth is four times that of the space between any 

 two adjacent paths of the teeth in the ground. Srdly. There are no 

 simple means of lifting the machine wholly out of the ground : the front 

 part may be raised, but the hind part remains. 



Kirkwood's grubber, an improvement on Finlayson's, was intended to 

 remedy some of these faults. For the third one he had a very neat 

 remedy, which is best understood by the drawing which represents the 

 frame-work in two different portions, depending on the degree to which 

 the handles are depressed. (See p. 98, Low's ' Practical Agriculture.') 

 It wdll be seen that the frame-work is lifted partially out of the ground 

 by this means, both ends being raised at once by depressing the handle. 

 In this machine the 2nd fault is also remedied by an arrangement of the 

 teeth, such as that represented in the annexed figure. It wuU be seen 

 that the distance between any two teeth is much more than twice the 



