The imaterp motion is taming doer 40; recoil 40 or 50 reetoeutione per etiosite and the Warr l'or quires two or three essieseets contently rifi*Yei in sharpening his tools.. When preporly flanked add smoothed, n pasteboard cylinder% laaeleVe6 -eetepeamdes, by au itmagibi bility, for the great labs. *ad expence which its construction. has created..
A second practical improvement in tokenism of the common. description consista in the substitution of cast. iron for mood, in the construction of the connecting frames. This improvement is now ems Moe to almost every description of niaelainery y and .when applied. to the coleader, it is of• more than usual advantage, because, independently of the ao. 'cession of strength and diminution of space occu pied, the total exemption of iron from warping is • of peculiar advantage in an engine so rapidly exposed to alteration of temperature as the caleeder must be. , The entire exemption of iron framing from combus tleaforins also another advantage of seine import woe in an engine hequently heated by the applica ilea of red-hot cylinders of iron. With this cursory aniline of general improvement, the next object .of the premed article is to afford a description of oaks Aare. in their present state of improvement, referring illuatmtion to the figures which are delineated in the Plate.
A representation of a common smoothing calen der, combining in its construction all the improve ments which have been detailed; will be found re presented by fig. 1. Plate X.T.X.
The framing of this calender, are well as of the glazing calender (fig. 2.), and which will afterwards be noticed, is represented as composed partly of iron and partly of wood; the upright posts which form the lateral connections, and which contain the /touches or sockets in which the axes or journals of the cylinders revolve being of the former substance, whilst the horizontal parts at top and bottom are re presented as of the latter. The latter, however, may also be very advantageously cast in iron.
The constituent parts of this calender are as• foi low : MA is the chief or main cylinder, which is re presented as 24 inches in diameter, and five feet in length, betwixt the connecting and compressing plates at the extremities. It must, however, be
premised, in order to avoid misconception, that dif ferent Engineers adopt different dimensions for their cylinders ; and that those adopted and specified in the representations given, are merely selected as specimens of such diameters as are in general use, and found to answer their end sufficiently ; but they may unquestionably be either extended or contract ed, according to particular circumstances, without any perceptible alteration of effect, provided care be taken that the ratio of velocity be always correspon dent with that of dimension.
BB are two cylinders of cast km externally turn ed until perfectly smooth. Their diameter is fixed at six inches each, allowing the substance of iron to be one and a half inches, and leaving a central cavi ty or perforation of three inches diameter, for the reception of red-hot cylinder, of cast iron, when the calendar is required to operate at a heated, tempera ture. Both extremities are perfectly open, in order that the heated cylinders, which, for the sake of con venient exposure in the furnace, should not exceed 12 or 36 inches in length, may be easily introduced at one end, and, after cooling, may be expelled at the other by fresh cylinders from the furnace. Their diameter should so _fir correspond with that-of the The cylinders CC, like the main cylinder A, ought to be constructed of compressed pasteboard, and their diameter assumed to be 12 inches. These five cylinders, with the wheels which put them in motion, constitute the whole dynamical or moving apparatus or the (*ender ; and, at the dianieteve which have been assigned to them, will occupy, when in contact fit for working, a space of five feet perpendicular in whole. To this muse be added the thickness of the top and bottom parts, and an allow ance of two or three inches vacancy to clear these from the upper and lower cylinders. A space in whole of abort two feet will be sufficient for these purposes, and the total altitude of the calender from the floor to the vertex will be about seven float.