Procure a large cask, and place it in the vicinity of places infested with rats. During the first week, this vessel is employed only to allure the rats to visit the solid top of the cask, by means of boards or planks arranged in a sloping direction to the floor, which are to be strewed with oatmeal daily, or any other food grateful to the palate.--Being thus lulled into security, and accustomed to find a regular supply for their meals, a skin of parchment is substituted for the wooden top of the cask, and the former is cut for several inches in the centre in transverse directions, so as to yield on the slightest pressure. At the same time, a few gallons of water, to the depth of six or seven inches, are poured into the empty cask, in the middle of which a brick or stone is placed, so as to project one or two inches above the fluid, and afford to one rat a place of refuge. These measures being taken, the top of the cask should be furnished with the proper baits, in order to induce the marauders to repeat their visits. No sooner does one plunge through the section of the parchment into the vessel, than it retreats to the brick or stone, and commences its lamentations for relief. Others follow, and share the same fate. A dreadful conflict then commences to obtain possession of the dry assylum. Battles follow in rapid succession, attended with such loud and noisy shrieks, that all the rats in the neighbourhood hasten to the fatal spot, where they experience similar disasters. Thus, hundreds may be caught by stratagem, which might be greatly facilitated by exposing a living rat taken in a trap, or purchased from a professional rat catcher. _Important to Millers._--A very valuable machine has lately been invented (and is now in operation) by Richard French, of Morrisville, (Pa.) for cleansing all kinds of grain and grass seeds. This machine cleanses the grain completely of the white cap, and at the same time rubs off the dust that always adheres to grain, and is the cause of specks in flour. The grain at the same time receives a fine polish. It operates equally on rye and buckwheat, cleansing it from all the dust and fuz which darken and cause grit in the flour, and are so liable to fret the bolting cloth. It is the opinion of a number of millers, that one barrel of flour may be obtained more from every hundred bushels of wheat, cleaned by this machine, than from the same quantity in the usual way. This machine will remain at Morrisville, for public inspection, a few weeks, after which it will be removed to Brandywine. Millers and others, who wish to make more and better flour, as there is no loss of grain, are invited to call and see the machine in operation. I believe they will not regret the time and trouble of so doing. [_Trenton paper._