The common jack by which meat is roasted is described by Mr. Babbage as "a contrivance to enable the cook in a few minutes to exert a force (in winding up the jack) which the machine retails out during the succeeding hour in turning the loaded spit, thus enabling her to bestow her undivided attention on her other duties." We have seen, years ago, in farm-houses, a man employed to turn a spit with a handle; dogs have been used to run in a wheel for the same purpose, and hence a particular breed so used are called "turnspits." When some ingenious servant-girl discovered that, if she put a skewer through the meat and hung it before the fire by a skein of worsted, it would turn with very little attention, she made an approach to the principle of the bottle-jack. All these contrivances diminish labour, and ensure regularity of movement;--and therefore they are valuable contrivances. A bell which is pulled in one room and rings in another, and which therefore establishes a ready communication between the most distant parts of a house, is a contrivance to save labour. In a large family the total want of bells would add a fourth at least to the labour of servants. Where three servants are kept now, four servants would be required to be kept then. Would the destruction of all the bells therefore add one-fourth to the demand for servants? Certainly not. The funds employed in paying for service would not be increased a single farthing; and, therefore, by the destruction of bells, all the families of the kingdom would have some work left undone, to make up for the additional labour required through the want of this useful contrivance: or all the servants in the kingdom would be more hardly worked,--would have to work sixteen hours a day instead of twelve.