THREE:Reciprocating tools are divided into those wherein the cutting movement is given to the tools, as in shaping and slotting machines, and machines wherein the cutting movement is given to the material to be planed, as in a common planing machine. Very strangely we find in general practice that machine tools for both the heaviest and the lightest class of work, such as shaping, and butting, operate upon the first principle, while pieces of a medium size are generally planed by being moved in contact with stationary tools.It is probable, however, that Aristotles partiality was determined more by the systematising and analytical character of his own genius than by the public opinion of his age; or rather, the same tendency was at work in philosophy and in art at the same time, and the theories of the one were unconsciously pre-adapted to the productions of the other. In both there was a decay of penetration and of originality, of life and of inspiration; in both a great development of whatever could be obtained by technical proficiency; in both an extension of surface at the expense of depth, a gain of fluency, and a loss of force. But poetry lost far more than philosophy by the change; and so the works of the one have perished while the works of the other have survived.
宝宝健康饮食是成长的关键，为了满足其生长发育所需要的各种营养，就必须对日常饮食做出合理安排。黄瓜和胡萝卜中含有丰富营养素，让宝宝吃得健康！
