Later, in 1804, Francis B. Stevens, of New Jersey, in an experimental boat on the Hudson, operated twin screws, and demonstrated their applicability to the requirements of marine practice.

It has a screw loose, an essential part is wanting.

I took out the little collimating screws first, then I drew out the tube, and in that I found a brass plate screwed on the diaphragm which contained the lines.

The ends of the bars gear into endless screws running the whole length of the furnace, whereby motion is given to the bars, and the coal is thus carried gradually forward.

This should be done after you have set the set screws in eccentric down solid on the shaft.

The upper plate terminates in two eyes, through each of which passes a pin, which also passes through the jaws of the bridle, connected by a double threaded screw to another bridle, which is jointed to the framing; the centre of the spring rests upon the axle box.

Taking the mean value, and bringing the slips to a common scale, Fig. 5 is obtained, which would approximately represent the relation between the efficiency of any one of these screws and its true slip, if this curve were applicable to full sized screws propelling actual ships.

The upper plate terminates in two eyes, through each of which passes a pin, which also passes through the jaws of the bridle, connected by a double threaded screw to another bridle, which is jointed to the framing; the centre of the spring rests upon the axle box.

All three were mounted in skeleton settings, | | with spiral screws, but the color of the gold setting of the | | flat diamond was not so dark as the other two.

For direct acting screw engines this species of valve is now extensively used.

As we neared her, however, she dwindled in size, and proved a rather dirty-looking merchant-craft with an auxiliary screw.

613. Q.Would not a screw combined with paddles act in a similarly advantageous way as a screw or paddles when aided by the wind? A.If in any given paddle vessel a supplementary screw be added to increase her power and speed, the screw will act in a more beneficial manner than if it had the whole vessel to propel itself, and for a like reason the paddles will act in a more beneficial manner.

The insides of the boxes are lined with press cloths, and when filled these cloths are carefully folded over the mall, which is now of the consistence of starch; and a heavy beam, worked on two upright three-inch screws, is let down on the lid of the press.

For instance, two bladed screws have frequently given better results than four bladed screws of smaller diameter, neglecting, of course, the question of vibrations.

I thought it nice ladylike work to manage such slight threads and turn such delicate screws; but fine as are the hairs of one's head, I shall seek something finer, for I can see how clumsy they will appear when I get on the eyepiece and magnify their imperfections.

Then this curve shows that considerable negative slips mean inefficient screws; that screws may have very different positive slips without any appreciable difference in their efficiencies; and that very large positive slips and inefficient screws may be companions.

He made all his own tools for working in wood and metals, and he constructed a lathe, by which he cut a perpetual screw in brass, a thing but little known, and which was the invention of Mr. Henry Hendley of York.

Q.From the greater proportionate resistance of small vessels, will not they require larger proportionate screws than large vessels?

'She certainly can leg it,' observed Ken, as he noticed how the whole fabric of the little craft quivered under the drive of the rapidly revolving screw.

It rotates round a hollow axis, through which a beam of light is thrown, and independent movements in the plane, at right angles to the axis, can be given to it in two directions, at right angles to one another, by turning two separate screws.

He is an engineer of treachery, fraud, and perfidiousness, and knows how to manage matters of great weight with very little force by the advantage of his trepanning screws.

The engine will draw fifteen heavy carriages fifty miles in an hour; and that remains as a noble feat, even though it be ascertained that the engine could not jump over a brook which would be cleared easily by the veriest screw.

The part corresponding to C, in Foucault's apparatus, was furnished with three vertical screws, by moving which the axis of figure was brought into coincidence with the axis of rotation.

Considering the brevity of their existence and the severe times they have had to pass through, the Lancaster-road Congregationalists must have worked hard and put a very vigorous Christian screw into operation to reduce their debt so rapidly.

He raised his hand to the wick screw of the lamp, waiting for her to pass through the room before turning off the flame which bathed him in its rays, giving him the effect of a Rodinesque incarnation of memory.