TWO:The reasons that favour combination of functions in machines, and the effects that such combinations may produce, are so various that the problem has led to a great diversity of opinions and practice among both those who construct and even those who employ machines. It may be said, too, that a great share of the combinations found in machines, such as those to turn [68], mill, bore, slot, and drill in iron fitting, are not due to any deliberate plan on the part of the makers, so much as to an opinion that such machines represent a double or increased capacity. So far has combination in machines been carried, that in one case that came under the writer's notice, a machine was arranged to perform nearly every operation required in finishing the parts of machinery; completely organised, and displaying a high order of mechanical ability in design and arrangement, but practically of no more value than a single machine tool, because but one operation at a time could be performed.The result of recent enquiries into the state of civilisation under the Roman Empire during the first two centuries of its existence, has been to suggest conclusions in many respects at variance with those formerly entertained. Instead of the intellectual stagnation, the moral turpitude, and the religious indifference which were once supposed to have been the most marked characteristics of that period, modern scholars discern symptoms of active and fruitful thought, of purity and disinterestedness both in public and private life, but above all of a religious feeling which erred far more on the side of excess than on the side of defect. This change of view may be traced to various causes. A new class of investigators have made ancient history an object of special study. Fresh evidence has been brought to light, and a more discriminating as well as a more extended use has been made of the sources already available. And, perhaps, even greater importance is attributable to the principle now so generally accepted, that historical phenomena, like all other phenomena, are essentially continuous in their movement. The old theories assumed that the substitution of Christian for what is called Pagan196 civilisation was accompanied by a sudden break in mens habits and ideas. But the whole spirit of modern philosophy has prepared us to believe that such a break is not likely to have ever occurred. And a new survey of the period in question is leading us to the conviction that, as a matter of fact, it did not occur.
TWO:3. The vertical movement of material, although it consumes more power, is more economical than horizontal handling, because less floor room and ground surface is required.
TWO:
TWO:Considered upon grounds of commercial expediency as a question of cost alone, it is generally cheaper to move material by hand when it can be easily lifted or moved by workmen, when the movement is mainly in a horizontal direction, and when the labour can be constantly employed; or, to assume a general rule which in practice amounts to much the same thing, vertical lifting should be done by motive power, and horizontal movement for short distances performed by hand. There is nothing more unnatural than for men to carry loads up stairs or ladders; the effort expended in such cases is one-half or more devoted to raising the weight of the body, which is not utilised in the descent, and it is always better to employ winding or other mechanism for raising weights, even when it is to be operated by manual labour. Speaking of this matter of carrying loads upward, I am reminded of the fact that builders in England and America, especially in the latter country, often have material carried up ladders, while in some of the older European countries, where there is but little pretension to scientific manipulation, bricks are usually tossed from one man to another standing on ladders at a distance of ten to fifteen feet apart.
