end on the left bank was to be movable， so that it might be raised by means of a counterpoise， as some canal bridges are managed.
this was certainly a considerable work， and though it was skillfully conducted， it took some time， for the mercy at this place was eighty feet wide. it was therefore necessary to fix piles in the bed of the river so as to sustain the floor of the bridge and establish a pile-driver to act on the tops of these piles， which would thus form two arches and allow the bridge to support heavy loads.
很快，塞勒斯.哈顿要动手制造玻璃的一切条件都具备了。最难制造的工具就是吹玻璃的吹管，这是一种五六英尺长的铁管，它的一端用来蘸液体玻璃。潘克洛夫把一条簿薄的铁片卷成枪筒形，也就做成了一根随时可以使用的吹管了。
3月28日，炉子已
第66章知识(21/23)