A survey of form and properties, however cursory, must involve measurement, otherwise an inventor cannot with accuracy embody a plan in a working machine, or know exactly how strong, elastic, or conducting a rod, a wire, or a frame is. Measuring instruments will be sketched, their use delineated, and the results of precise measurement noted as an aid to the construction of modern mechanism, the interchangeability of its parts, the economy of materials and of energy in every branch of industry. Next will follow a chapter noting tasks which Nature has long accomplished, and which Art has still to perform, as in converting at ordinary temperatures within the human body fuel energy into work. Plainly, a broad field opens to future invention as it copies the function of plants and animals; functions to be first carefully observed, then explained and at last imitated with the least possible waste of effort. The equipment and the talents for invention and discovery are now touched upon. First, knowledge, especially as the fruit of disinterested inquiry; Observation, as exercised by trained intelligence calling to its aid the best modern instruments; Experiment, as an educated passion for building on original lines. Then, in the mechanical field, we bestow a few glances at self-acting machines, at the simplicity of design which makes for economy not only in building, but in operation and maintenance. Either in designing a new machine, or in reaching a great truth, such as Universal Development, there is scope for Imagination upon which we next pause for a moment. A succeeding chapter outlines how theories may be launched and tested, how analogy may yield a golden hint, the profit in rules that work both ways, or even in doing just the opposite of what has been done without question for ages past. [Illustration: Copyright, 1906, by Park & Co., Brantford, Ontario, Canada BELL HOMESTEAD, BRANTFORD, ONTARIO, CANADA. ALEXANDER GRAHAM BELL AND HIS DAUGHTER IN THE FOREGROUND. HERE THE TELEPHONE WAS PERFECTED IN 1874. Now the Home of the Bell Telephone Memorial Association.] From this brief consideration of method we now pass to a few men who have exemplified method on the loftiest plane; we come into the presence of Newton, the supreme generalizer, and observe his patience and conscientiousness, as remarkable as his resourcefulness in experiment, in mathematical analysis. Even greater in experiment, while lacking mathematical power, is Faraday, who next enlists our regard. This great man, more than any other investigator, laid the foundations of modern electrical science and art. Moreover he distinctly saw how matter might reveal itself in the ‘radiant’ condition now engaging the study of the foremost inquirers in physics.