Mr. Keely gives a few introductory words concerning the necessary graduating of his instruments, for effecting conditions necessary to ensure perfect sympathetic transmission, which will serve to show how great are the difficulties that have been attendant upon getting his machines into a condition to control and equate the differentiation in molecular masses, requiring greater skill than in researching the force of a sunbeam. He writes:--The differentiation in molecular metallic masses, or grouping, is brought about in their manipulations in manufacturing them for commercial uses; in the forging of a piece of metal, in the drawing of a length of wire, and in the casting of a molten mass to any requisite form. The nearest approach to molecular uniformity in metallic masses is in the wire drawn for commercial uses, gold and platina being the nearest to freedom from differentiation. But even these wires, when tested by a certain condition of the first order of intensified molecular vibration for a transferring medium between centres of neutrality, I find to be entirely inadequate for the transfer of concordant unition, as between one and the other, on account of nodal interferences. We can appreciate the difficulty of converting such a medium to a uniform molecular link, by knowing that it can be accomplished only after removing all nodal interference, by inducing between the nodal waves a condition in which they become subservient to the inter-sympathetic vibratory molecular link of such structure or wire. Therefore, it is necessary to submit the wire to a system of graduation in order to find what the combined chords of these nodal interferences represent when focalized to one general centre. Then the differentiation between these nodal waves and the inter-molecular link must be equated, by what I call a process of vibratory induction, so as to induce pure concordance between one and the other. To elaborate on this system of graduation, for effecting conditions necessary to ensure perfect and unadulterated transmission, would make up a book that would take days to read and months to study.