The power required to drive a mowing machine at work may be resolved into direct draft and side draft. A good mowing machine should be so balanced between the driving wheels and the cutter bar, by placing the line of draft nearer or further from the heel of the bar, that ordinarily there will be little or no side draft. If so placed, the end of the tongue will sometimes, when at work, be drawn toward the standing grass, and sometimes thrown away from it by the side draft. Practically, side draft is of small account in a good machine. The direct draft depends upon three causes, and may be resolved into three parts: 1, The draft of the machine itself, on its own wheels, on the ground; 2, The power required to give motion to the gearing and the knife; 3, The resistance offered by the grass or other substance cut. The power required to draw the machine on its own wheels depends upon the size of the wheels, the perfection of the axles, and the smoothness of the ground, and, other things being equal, upon the weight of the machine; and in a machine weighing 600 lbs., should not, on a smooth firm turf and level field, be more than 75 to 100 lbs Adding to the weight of the machine would add to the draft just in proportion, whether that added weight be in the machine or in a driver on it. Suppose the machine to weigh 600 lbs. and the draft to be 80 lbs., put a driver of 150 lbs. on the seat, and you have increased the draft 25 per cent, or to 100 lbs., while the power required to drive the knife and to cut the grass remains unchanged, and you have only increased the draft 20 lbs. The power to drive the knife and gearing depends upon the perfection of the gearing and the weight and velocity of the knife. A machine that in proper order may not require more than 10 or 20 lbs. of power, may require ten or twenty times that amount from deficiency of oil, collection of dirt in the gearing, gum on the knife, or loosening of the connections of the pitman by wearing or otherwise. The resistance of the grass to be cut will vary with every change of condition, kind, and thickness of grass, and every variation in the condition of the knife and rapidity of stroke. The greater the velocity of a cutting edge, after the velocity is once obtained, the less power is required to do a given amount of work. The direct draft of a good machine, working under the most favorable circumstances, has been determined by experiment to be less than 300 lbs.; but those favorable conditions are not always to be obtained, so that the draft must many times be much heavier. The power of a machine to cut, other things being equal, depends upon the hold the wheels have upon the ground; when the second and third causes combined are sufficient to overcome the hold the wheels have, the latter slide, the knife stops, the machine is clogged. The heavier the machine, the less likely this is to occur; putting a heavy driver on the seat will sometimes carry a machine through when with a lighter one it would clog. When the knife reaches the end of the stroke, its momentum is considerable, and it requires nearly as much power to stop it as it did to start it to make the stroke; it would require quite as much if it were not for the loss of some power by the friction of the knife in the guards. Now if the joints of the pitman and connections are all perfect, this stopping occurs when the crank passes the centre of the shaft driving it, and the remainder of the momentum of the knife is expended upon the crank in the direction of its length and at right angles to the driving power, so that none of that is used up in stopping the knife. But if these joints of the pitman are loose, so that there is a little play, and the crank can pass the centre before the knife reaches the end of the stroke, this momentum will be expended in opposition to the driving power, and will of course increase the power necessary to work the machine by so much as is necessary to overcome the momentum of the knife; again, the crank beginning to act upon the knife after it has passed the centre to make the return stroke, the knife must start with a greater velocity, causing another loss. Now, put the same machine into the grass, and the grass operates to stop the knife as soon as the crank allows it to stop, thus saving the momentum that was expended upon the crank in opposition to the driving power, and also shortening the stroke and saving power that way. Supposing, to illustrate, that there is a play of 1/2 inch in the joints, then the knife running out of the grass will be thrown to the extreme length each way, and will add 1 inch to the length of the stroke, increasing the power necessary to make it. If it requires a certain number of pounds power to make a stroke of 3 inches in length, it will require 33-1/8 per cent more power to make a stroke of 1 inches in Length in the-same time. Whenever these amounts of power lost in this way equal the power required to cut the grass, then the machine will draw just as heavily out of the grass as in it. From these premises many deductions may be made as to the care and practical use of mowing machines. Nest Eggs, To make Take an ordinary hen's egg, break a small hole ill the small end, about 3/8 of an inch in diameter, extract the contents, and, after it is thoroughly clear inside, fill it with powdered slaked lime, tamping it in order to make it contain as much as possible. After it is full, seal it up with plaster of Paris, and you have a nest egg which can not be distinguished by the hen from the other eggs, and one which will not crack (like other eggs) by being frozen.