Its Oblique Advance Over Eight Points example essay topic

The agriculture of Hellensitic Italy was transformed not only by the introduction of a large number of technical innovations, but also by a profound structural change. The last 2 centuries BC witnessed decisive steps towards the establishment of large scale estates, latifundia, which were to play an important role in the course of the empire. Even though the cultivation units remained relatively small for a long period, there was gradual transition to more extensive farming, largely based on slave labour. Fortunately, we are able to gain a detailed insight into the agricultural life of the time. About 160 BC, a Roman statesman, Cato the Censor (234 BC-149 BC) wrote a book called De agricultura ("About Agriculture").

It is not a well arranged manual, but rather a collection of unconnected notes comprising, apart from general instructions and a mention of religious customs, a description of two of Cato's own estates near the border of Latium and Campania. One farm - with an extent of 240 iugera (about 60 ha. or 150 acres), managed by 13 people (mainly slaves) - specialised in the cultivation of olives. The other specialised in viticulture, occupied 100 iugera (about 25 ha. or 60 acres) and was managed by 16 people. Even though the descriptions refer to these two particular farms, they are doubtless fairly representative of normal cultivation units in Late Republican Italy.

Besides workers and animals, all kinds of tools and equipment are listed, including the precise number of spades, axes, tongs, working tables and so on used at each farm. As well as this, specialised agricultural equipment, Cato describes a series of machines, showing that - in spite of his well-known aversion to everything foreign - he was perfectly aware of the recent achievements of Greek technology. The olives were crus he in 5 edge-runner mills (trapeta 1) of various sizes (a recent invention), and the pulp was then transferred to five presses of the most recent models, at least some of which were provided with block and tackle to hoist the weights. The wine was pressed in similar machines; and there was a series of mills to process grain cultivated for household use: on the olive farm, there was an Olynthian Mill, an improved saddle quem, a rotary hand mill (invented about 300 BC), and a donkey mill. In the vineyard, there was one Olynthian Mill and three donkey mills. Cato describes his machines in detail, but they are best illustrated by later archaeological finds - from the cities of Vesuvius, in particular.

Variants of the same devices were found throughout the Roman Empire, from Britain and the Rhine frontier to Africa and South East Asia. Some of the machines survived in Mediterranean countries well into the 20th Century. A reconstruction of a lever-and-drum press for crushing olives, or grapes for winemaking. The olive pulp / grapes were placed on the press bed (a) and covered with a lid (b). The pressing beam (c) was drawn down with levers (e) and a rope running around a drum (d), shown here in the foreground. (Reconstructed from Article) (1.) Trapeta (edge-runner mills) were two hemispherical segments hanging on a horizontal beam which were rolled over the olives in order to separate the pulp from the stones (think of a barbell being used to crush olives on a stone block).

Source: Burenhult, G. (1994), Old World Civilisations: The Rise of Cities and States, Uni. QLD Press, Brisbane (AUS). THE ARCHIMEDEAN SCREW The Archimedean screw is a device used to elevate water for irrigation on fields which are higher than the source of water. A long handle extends out of the upper end of the device which is cranked by hand. This action causes the spiral chambers inside the device to rotate. The rotation forces water up into higher 'compartments' whilst the spiral nature of the screw prevents the water flowing into lower 'compartments'.

Water for irrigation emerges at the top side of the device. Variations of this device is still used in some countries today. Vitruvius (c. first century BC), De Architecture, Book X, Chapter VI, The Water Screw 1. There is also the method of the screw, which raises a great quantity of water, but does not carry it as high as does the wheel. The method of constructing it is as follows. A beam is selected, the thickness of which in digits is equivalent to its length in feet.

This is made perfectly round. The ends are to be divided off on their circumference with the compass into eight parts, by quadrants and octants, and let the lines be so placed that, if the beam is laid in a horizontal position, the lines on the two ends may perfectly correspond with each other, and intervals of the size of one eighth part of the circumference of the beam may be laid off on the length of it. Then, placing the beam in a horizontal position, let perfectly straight lines be drawn from one end to the other. So the intervals will be equal in the directions both of the periphery and of the length. Where the lines are drawn along the length, the cutting circles will make intersections, and definite points at the intersections. CONSTRUCTION OF THE WATER SCREW (above) 2.

When these lines have been correctly drawn, a slender withe of willow, or a straight piece cut from the agnus cast us tree, is taken, smeared with liquid pitch, and fastened at the first point of intersection. Then it is carried across obliquely to the succeeding intersections of longitudinal lines and circles, and as it advances, passing each of the points in due order and winding round, it is fastened at each intersection; and so, withdrawing from the first to the eighth point, it reaches and is fastened to the line to which its first part was fastened. Thus it makes as much progress in its longitudinal advance to the eighth point as in its oblique advance over eight points. In the same manner, withes for the eight divisions of the diameter, fastened obliquely at the intersections on the entire longitudinal and peripheral surface, make spiral channels which naturally look just like those of a snail shell. 3. Other withes are fastened on the line of the first, and on these still others, all smeared with liquid pitch, and built up until the total diameter is equal to one eighth of the length.

These are covered and surrounded with boards, fastened on to protect the spiral. Then these boards are soaked with pitch, and bound together with strips of iron, so that they may not be separated by the pressure of the water. The ends of the shaft are covered with iron. To the right and left of the screw are beams, with crosspieces fastening them together at both ends. In these crosspieces are holes sheathed with iron, and into them pivots are introduced, and thus the screw is turned by the treading of men.

4. It is to be set up at the inclination corresponding to that which is produced in drawing the Pythagorean right-angled triangle: that is, let its length be divided into five parts; let three of them denote the height of the head of the screw; thus the distance from the base of the perpendicular to the nozzle of the screw at the bottom will be equal to four of those parts. A figure showing how this ought to be has been drawn at the end of the book, right on the back..