Mr. Coane, the respondents' expert engineering witness, admitted that each had both a revolving crank and an oscillating crank. There were two differences claimed by the respondents to exist between the two sets of mechanism. The reference in the specification to an adjustable pitman was one. I have already expressed my view generally that this was nothing new, but may here add that in cross-examination Mr. Coane stated that in general mechanical contrivances adjustable pitmen are commonly known among engineers as a means of altering velocity, and that was known all his time. He stated, too, that he had never seen anything like an adjustable pitman in varying differential motion in the case of concentrating tables. To that, however, I attach no importance. Differential motion was an old function even as applied to concentrating tables long before the date of the patent. Beyond doubt an adjustable pitman was an old device in connection with differential motion. The use of it for the present purpose involved no ingenuity. The patentee simply drew on the common stock of knowledge. The other suggested difference consisted, as stated by Mr. Coane, in the different direction of the second pitman - which he called, in the Wilfley machine, the second toggle bar - from that of the second pitman in the respondents' machine, where he styled it a connecting rod. In the latter it is almost at right angles to the oscillating crank, in the former almost in the same line. The result, he said, was a difference in movement, the movement in the respondents' case decreasing more suddenly than in the Wilfley. That, said Mr. Coane, is the result, by which he meant the necessary result, of any toggle joint. A toggle joint is simply a joint with two moveable struts. He says there is necessarily a difference in the angles between the oscillating cranks and the respective pitmen, which are attached to them and connected with the lever. This gives rise to a difference in speed, and for that reason he would not call the one apparatus a mechanical equivalent for the other. He verbally differentiates between the movements thus: In the Wilfley there is first a slow movement forward, then accelerated, then it stops. Then a start back with accelerating velocity, then retardation more slowly, and finally a stop. In the Card machine, first slowly forward, then acceleration, and a sharp dying away to stop; a start back with rapid acceleration and gradual retardation till the stop. He adds, the character is the same but the velocity is different. There can be no doubt that in each case there is a bumping action, with a differential velocity. To me he said that, so long as the style of mechanism adopted by Wilfley is used, he did not think it possible to get the same curves of velocity as those produced by the Card, nor curves so nearly resembling them as to be indistinguishable by measurement. He finally says - You want in these tables a sudden stop and a quick return, and you get it in the respondents' case, but not with the Wilfley. On the face of this evidence there appears to be some substance in the distinction between the two trains of mechanism. But the evidence of the engineers called for the petitioners in my opinion completely answered any difficulty occasioned by it. Summing up the result of the testimony of Mr. Bernhard Smith and Mr. Anderson (Mr. Mitchell had left Melbourne before Mr. Coane's opinion was given and was unobtainable) the situation appears to be this. There is a theoretical difference in the rate of velocity at a given point between the two types of mechanism. That difference can be brought down to within two or three per cent., and to no nearer approximation. In other words, as stated by Mr. Bernhard Smith, if at any given point of the revolution the Wilfley velocity were 3 feet per second, the Card velocity might be 3 feet and a ¼ of an inch. You could so arrange the parts as to make the greater speed to that extent fall on the side of the Wilfley. But although theoretically there would always be this slight difference, arising from the non-identity of the precise position of the two oscillating cranks, it would, in any case, be utterly negligible as a practical matter. It would be almost imperceptible. Even an expert engineer would have difficulty in determining it. But beyond that, the unavoidable imperfection of practical mechanical construction, and the necessary play in the joints and attachments of the parts, utterly destroys the theoretical precision of the difference in the positions of the oscillating cranks. A machine must have a play of 1-64th part of an inch in the different joints to permit of lubrication, and thus whatever theoretical difference exists is lost in practice. The two sets of mechanism I regard as substantially identical. In ingredients, arrangement, and functions, purpose. and result they are in substance the same. Apart from comparison between them, the evidence entirely satisfied me that the respondents' device was not novel. Mr. Coane certainly expresses the opinion that without invention an engineer would not previously have thought of adopting the oscillating crank in the Card mechanism. But the weight of opinion, as I am able to gather it, is the other way. Both Mr. Bernhard Smith and Mr. Anderson are emphatic that the respondents' device, like the Wilfley mechanism, was commonly known to engineers as applicable, and was applied, for the purpose of imparting differential motion. Mr. Smith was clear that before 1904, according to the common knowledge of engineers, it would have required no invention to substitute an ordinary oscillating crank for the toggle joint; and Mr. Anderson said that the Card device was, before 1904, the identical mechanism most used for getting differential motion in the way imparted by it, and was, in his opinion, a more obvious means of obtaining it than the Wilfley type. Mr. Rigby supported Smith and Anderson as to the practical identity of the two mechanisms, and the previous knowledge of the respondents' device. I find as a matter of fact, therefore, both as to the undergear and the actuating mechanism, they were in no way novel, presenting no new feature in design, construction, purpose, function, or result, and were part of the ordinary knowledge of mechanical engineers, and of other persons engaged in the art of concentrating ores.