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ONE:"The Governor-General of Belgium. TWO:There is, however, a principle in hydraulic machinery that must be taken into account, in comparing it with positively geared mechanism, which often leads to loss of power that in many cases will overbalance any gain derived from the peculiar action of hydraulic apparatus. I allude to the loss of power incident to dealing with an inelastic medium, where the amount of force expended is constant, regardless of the resistance offered. A hydraulic crane, for instance, consumes power in proportion to its movements, and not as the amount of duty performed; it takes the same quantity of water to fill the cylinders of such cranes, whether the water exert much or little force in moving the pistons. The difference between employing elastic mediums like air and steam, and an inelastic medium like water, for transmitting force in performing irregular duty, has been already alluded to, and forms a very interesting study for a student in mechanics, leading, as it does, to the solution of many problems concerning the use and effect of power.THREE:A book containing the pattern record should be kept, in which these catalogue numbers are set down, with a short description to identify the different parts to which the numbers belong, so that all the various details of any machine can at any time be referred to. Besides this description, there should be opposite the catalogue of pattern numbers, ruled spaces, in which to enter the weight of castings, the cost of the pattern, and also the amount of turned, planed, or bored surface on each piece when it is finished, or the time required in fitting, which is the same thing. In this book the assembled parts of each machine should be set down in a separate list, so that orders for castings can be made from the list without other references. This system is the best one known to the writer, and is in substance a plan now adopted in many of the best engineering establishments. A complete system in all things pertaining to drawings and classifications should be rigidly adhered to; any plan is better than none, and the schooling of the mind to be had in the observance of systematic rules is a matter not to be neglected. New plans for promoting system may at any time arise, but such plans cannot be at any [87] time understood and adopted except by those who have cultivated a taste for order and regularity.