EXCAVATING MACHINES, for digging and removing earth in extensive excavations, have occupied the attention of many ingenious men, and various machines for the purpose have been proposed and tried with different degrees of success. The great difficulty appears to consist in adapting any peculiar arrangement of mechanism which shall be capable of digging into the various kinds of earth. Were it only to operate upon a uniform mass, like soft clay, the task would be comparatively of easy accomplishment. Mr. G. V. Palmer, of Worcester, appears to have devoted himself with great assiduity to the con struction of an efficient excavating engine, and to have expended considerable sums in its attainment. In 1830 he took out his first patent " for a machine to cut and excavate earth," which we have perused at the Inrolment Office. This machine is designed, by the application of steam power, to loosen, dig up, and remove into a cart, earth from a canal or other cavity, and to move itself forwards as the excavation proceeds. In principle its leading arrangement resembles the dredging machines employed in clearing the beds of rivers and harbours; but it has several appurtenances, such as picks, for loosening the earth, cutters, for separating it, and scrapers, for filling it into the scoops or elevators, which convey it into the cart by which it is moved away. The machine is mounted upon four wheels, and gradually moves forward upon a temporary railway as the excavation proceeds. The moving power is applied to the axis of a fly-wheel, and to the same axis is fixed a drum or pulley, around which passes an endless pitched chain, that gives motion to another drum or pulley, which revolves in bearings fixed to the upper ends of two long cheeks or supports. Around this second drum passes another endless chain, which gives motion to a third drum or pulley, which is of a quadrangular figure, and turns on an axis in the lower ends of the long cheeks ; to this last-mentioned chain are fastened a series of earth scoops, which are successively brought into operation in taking up the earth. So far the machine resembles the common ballast engine ; we have therefore to describe how the several actions of picking, digging, and projecting the earth are effected. A third endless chain is actuated by the drum on the main axis, and gives motion to a spur-wheel, which drives another toothed wheel attached to the fore wheels of the carriage, which gradually advances it. By an ingenious system of levers, connected to a crank on the
main axis, a row of pick-axes, a row of cutters, and a row of scraping shovels, are alternately brought into action. When the pickers have descended and loosened a portion of earth, the cutters succeed, and separate it from the mass, and this separated portion is immediately afterwards drawn forwards by the scraping shovels into the scoops, which, by the action of the machine, are brought into the required position on one of the sides of the revolving quadran aular drum ; the filled scoops thence proceeding to the top of the machine by the revolution of the attached endless chains, discharge their contents into a cart or waggon to be conveyed away. The same gentleman patented another engine for this purpose in 1832. This consisted of an excavating cart and plough united, to be worked by horses or other power. The cart wheels are made considerably wider than those in common use, and the interior portion of the ring of each wheel is made into a series of earth boxes; these earth boxes are made to open inwards, and also towards the centres of the wheels. Underneath the cart, immediately adjoining each wheel, is placed a plough, for raising and turning the earth into the boxes, as the cart is moved forwards ; the wheels at the same time turning round, bring up the earth and deliver it into the body of the cart. When a sufficient load has been thus deposited in the cart, the ploughs are raised from the ground by means of a lever, and then the cart can be drawn in every respect as a common cart, to the place intended for the deposition of the excavated earth, where it is to be unloaded by withdrawing a pair of bolts, which allow the bottom of the cart to fold downwards sufficiently to permit the earth to escape. There are many circumstances where the appli cation of excavating machinery of this kind might be employed to advantage. Under the head BARROW will be found some useful information relating to this subject, which we have repeatedly seen practised on the great scale.