Lastly, we may point out that the durability of the apparatus will be considerable.  There is no wear except at the moment when the rope is passing round the drum, and even then there need be no slipping or grinding.  The apparatus worked in the Neva was in very good condition after running for four months day and night.  After five months about one-fifth of the parachutes had to be replaced, but after seven months the hemp rope still showed no signs of wear.  We think we have said enough to show that for certain purposes, and especially, as we have, already mentioned, for irrigation purposes, the new motor is well worthy of a careful and extended trial.  It may be questioned even whether we have not here the germ of an idea which may hereafter enable us to solve one of the most interesting and important of engineering problems, viz., the utilization of the great store of power provided for us twice daily in the ebb and flow of the tide.—­The Engineer.

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IMPROVED SHAFTING LATHE.

Our engraving represents a new departure in shaft turning lathes, and is the result of thirty years’ experience in the manufacture of shafting, with many years’ study, to perfect a machine of the greatest practical capacity and efficiency.

[Illustration:  IMPROVED SHAFTING LATHE.]

The principal points of difference from a common engine lathe are readily distinguished, among which may be mentioned the absence of centers and tail stock, a traveling head with hollow driving spindle, and a stationary tool rest and water tank.  By dispensing with a tail stock a much shorter bed may be used, and the hollow driving spindle enables any length shaft to be turned, with one setting of the tools.  The tool rest is so arranged as to allow of perfect lubrication of the tools, keeping the shaft cool, and at the same time holding it perfectly rigid and strong; the operator is not required to travel the length of the bed, but remains near the driving belt, feed gearing, etc.  Power is communicated to the driving spindle by means of a sliding pinion on a splined rod inside the bed, the driving belt and gears being at the end.

The driving head, after having traveled the length of the bed and turned a shaft, is returned by a quick feed, and stops automatically, allowing nearly time enough for the operator to grind tools and be ready with another shaft, thus economizing the time completely.

Wood, Jennison & Co., Worcester, Mass., are the makers, and they say that with a good quality of iron they have turned three hundred feet of two inch iron in ten hours.

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POWER STRAIGHTENING MACHINE.