Not every farmer has atopped to stndy the physios of the doubletree. Very few doubletrees are made with three holes in tbern on a line, as will be seen in Fig. A. Tbey are of tener ruade as in Fig. B, so that the strain will not be so Hable to split the wood. You seldom ever see one made as in Fig. C, yet one is oooasionally made in this way with rigid attachment. Now let us look at them closely. When the three holes are on a line, it matters not which horse is ahead, both pull an equal share of the load, as will be seen by Fig. D, where both euds are equal. When the holes are out of line, as is usually the case on doubletrees, 'iike B, it wiH be seen at a glance that the borse that gets behind is not only behiud, but he eujoys the short end of the doubletree and is pulling more than bis share of the load. This ia showu in Fig. E. Should the sides of this doubletree be reversed the horse that goes ahead -will have the short end and will be pulling the greater part of the load, as in Fig. F. Should you be unf ortunate enough to have a doubletree like Fig. C it will be seen by glancing at Fig. G that the horse which is behind not only enjoya being behind time, but he is by his laziness compelling his mate to pull the greater share of the load. I give these figures f or the boys on the farm to ponder over. These lessons will not only be found interesting, but will be valuable for any one to know who has to work with horses, saysa practical farmer, who expresses the foregoing ideas in the Iowa Homestead.