On one point alone, belonging to the domain of science, do the Assyrian representations of their life enable us to comprehend, at least to some extent, their attainments. The degree of knowledge which this people possessed on the subject of practical mechanics is illustrated with tolerable fulness in the bas-reliefs, more especially in the important series discovered at Koyunjik, where the transport of the colossal bulls from the quarry to the palace gateways is represented in the most elaborate detail. [PLATE LXXXVIII.] The very fact that they were able to transport masses of stone, many tons in weight, over a considerable space of ground, and to place then on the summit of artificial platforms from thirty to eighty (or ninety) feet high, would alone indicate considerable mechanical knowledge. The further fact, now made clear from the bas-reliefs, that they wrought all the elaborate carving of the colossi before they proceeded to raise them or put them in place, is an additional argument of their skill, since it shows that they had no fear of any accident happening in the transport. It appears from the representations that they placed their colossus in a standing posture, not on a truck or wagon of any kind, but on a huge wooden sledge, shaped nearly like a boat, casing it with an openwork of spars or beams, which crossed each other at right angles, and were made perfectly tight by means of wedges. To avert the great danger of the mass toppling over sideways, ropes were attached to the top of the casing, at the point where the beams crossed one another, and were held taut by two parties of laborers, one on either side of the statue. Besides these, wooden forks or props were applied on either side to the second set of horizontal cross-beams, held also by men whose business it would be to resist the least inclination of the huge stone to lean to one side more than to the other. The front of the sledge on which the colossus stood was curved gently upwards, to facilitate its sliding along the ground, and to enable it to rise with readiness upon the rollers, which were continually placed before it by laborers just in front, while others following behind gathered them up when the bulky mass had passed over there. The motive power was applied in front by four gangs of men who held on to four large cables, at which they pulled by means of small ropes or straps fastened to them, and passed under one shoulder and over the other--an arrangement which enabled them to pull by weight as much as by muscular strength, as the annexed figure will plainly show. [PLATE LXXXIX., Fig. 1.] The cables appear to have been of great strength, and are fastened carefully to four strong projecting pins--two near the front, two at the back part of the sledge, by a knot so tied that it would be sure not to slip. [PLATE LXXXIX., Fig. 4.] Finally, as in spite of the rollers, whose use in diminishing friction, and so facilitating