The later English artists have somewhat changed the mode of communicating motion to the slides, by attaching the screws pdrmanently to the micrometer head and tapping each micrometer screw into its slide.
One reply to this is that it is not difficult to determine from time to time the errors of the screws and to apply the necessary corrections to the observations.
"I want to stop him before he screws up a real missing person case by sending the police off on a snipe hunt," he snarled.
Not if it screws up what we're doing... what we should be doing right now, instead of talking about my love life.
There are all kinds of different tools, pitons, hammers to set pitons, ice screws, pound-ins, ice hooks, wired nuts and cams—different stuff for different surfaces.
P. io) claim that became universal; the methods of illumination were improved; and micrometers with screws of previously unheard of fineness and accuracy were produced.
The eyepiece slides into the tube cd, which screws into the brass ring ef, through two openings in which the oblong frame, containing the micrometer slides, passes.
In the middle of this slide a stiffly fitting brass disk is inserted, to which a small turn-table motion may be communicated by an attached arm, acted on by two fine opposing screws accessible to the astronomer; and by their means the " fixed web " may be rendered strictly parallel with the movable one.
I, 2 and 3), used to bolt the head of one of the screws, and the instrument was provided with a slipping piece, giving motion to the micrometer by screws acting on two slides, one in right ascension, the other in declination, so that " either of the, webs can be placed upon either component of a double star with ease and certainty (Mem.
The five fixed webs are attached to the table which is secured to the bottom of the box by the screws p. The three movable webs are attached to the projections XX on the frame aa.
The microscope or viewing telescope is fitted with a spider-line micrometer having two screws at right angles to each other, by means of which readings can be made first on one reseau-line, then on the star, and finally on the opposite reseau-line in both co-ordinates.
Two other screws, o, p, the heads of which are not graduated, give motions to the whole micrometer box through t 1 mm.
By means of one of the micrometer screws X place the star's image in the middle of the six parallel webs which are moved by X.
But a little consideration will show that when the plate is reversed 180° the effects of errors of the screws produced by wear are practically eliminated.
The absolute freedom of the derived co-ordinates from the effects of wear of the screws in the mean of measures made in reversed positions of the plate.
Fur Instrumenten- the focussing screws 0 1 and 02.
The manufacture of woollens, linens, hosiery, furniture, gloves, paper, machinery and tools, carriages, nuts and screws, needles and other hardware goods is carried on.
There are three Li ting - typical methods: (I) A direct pull may be applied to the hook, either by screws, or by a cylinder fitted with is piston and rod and actuated by direct hydraulic or other pressure, as shown diagrammatically in fig.
Where the rail-gauge is narrow and great weight is not desired, blocking girders are provided across the under side of the truck; these are arranged so that, by means of wedges or screws, they can be made to increase the base.
A coarse screw-thread is formed in the upper part of the inner cup, and this screws on to the end of the iron bolt by which it is supported.
The coils of the electromagnets are differentially wound with silk-covered wire, 4 mils (= 004 inch) in diameter, to a total resistance of 400 ohms. This differential winding enables the instrument to be used for " duplex " working, but the connexions of the wires to the terminal screws are such that the relay can be used for ordinary single working.
By means of several adjusting screws the force and frequency of these blows can be exactly regulated.
6) for cleaning or renewal; the adjustment of the bearings is made by screwing up the cage cap b, locked by a special washer and the two screws a, a (figs.
Among the city's manufactures are oxide of tin and other chemicals, iron and steel, leather goods, automobiles and bicycles, electrical and telephone supplies, butted tubing, gas engines, screws and bolts, silk, lace and hosiery.
Ball, Theory of Screws (Dublin, 1876); and papers in Phil.
In Rowland's dividing engine the screws were prepared by a special process devised by him, and the resulting gratings, plane and concave, have supplied the means for much of the best modern optical work.
Focus, would correspond with 2" of arc. But, after all, this is no practical difficulty, for screws can be used to separate the lenses, and, by these screws, as in a Gascoigne micrometer, the separation of the lenses can be measured; or we can have scales for this purpose, read by microscopes, like the Troughton 1 circles of Piazzi or Pond, or those of the Carey circle, with almost any required accuracy.
The slides are moved by the screws a and b, the divided heads of which serve to measure the separation of the segments.
These screws are turned from the eye-end by bevelled wheels and pinions, the latter connected with the handles a', b'.
The third method is the most symmetrical of all, both in observation and reduction; but it was not employed by Bessel, on the ground that it involved the determination of the errors of two screws instead of one.
4) that Bessel had indicated, by notes in his handbooks, the following points which should be kept in mind in the construction of future heliometers: (I) The segments should move in cylindrical slides; b (2) the screw should be protected from dust; 6 (3) the zero of the position circle should not be so liable to change; 7 (4) the distance of the optical centres of the segments should not change in different position angles or otherwise; 8 (5) the points of the micrometer screws should rest on ivory plates; 9 (6) there should be an apparatus for changing the screen.'° Wilhelm Struve, in describing the Pulkowa heliometer,' 1 made The distances of the optical centres of the segments from the eye-piece are in this method as I; secant of the angle under measurement.
4 I criticizing Bessel's choice of methods, and considering the loss of time involved in each, it must be remembered that Fraunhofer provided no means of reading the screws or even the heads from the eye-end.
He considered that the changes were due to wear, which would be much lessened if the screws were protected from dust.
But the method is not available if the separation is to be measured by screws; it is found, in that case, that the direction of the final motion of turning of the screw must always be such as to produce motion of the segment against gravity, otherwise the " loss of time " is apt to be variable.
Thus the simple connexion of the two screws by cogwheels to give them automatic opposite motion is not an available method unless the separation of the segments is independently measured by scales.
Means of measuring the focal point were provided; symmetrical motion was given to the slides; scales on each slide were provided instead of screws for measuring the separation of the segments, and both scales were read by the same micrometer microscope; a metallic thermometer was added to determine the temperature of the scales.
Side-shake is prevented by the screws and pieces k, k, k, k.
Accordingly, in reading the scales A and B (attached to the slides which carry the two halves of the object-glass), it is only necessary to turn the screws until the fixed 1 The primary object was to have the object-glass mounted in steel cells, which more nearly correspond in expansion with glass.
The water-tight lining may be either a wrought iron tube, which is pressed down by jack screws as the borehole advances, or cast iron tubbing put together in short complete rings, in contradistinction to the old plan of building them up of segments.
The hand-wheel that screws the gun and cradle down at the same time screws the sight up, and vice versa.
The probable errors and eccentricities of small micrometer-screws have been carefully investigated to ± 0.00001 inch; but the accuracy of leading screws used in workshops has not been sufficiently verified.
For some engineering purposes it would appear to be desirable to produce master-screws to an accuracy of (1/2000)th of an inch to the foot of screw, so as to serve indirectly for the verification of "guiding screws" for general use in workshops.
The fallers are travelled forwards by means of screws, and when at the end of the screw are dropped automatically into the thread of a receiving screw fixed below, which carries the fallers back to their starting point to be risen by cams into the top pair of screws thus to repeat their journey.
These rise 'Two screws, of different pitch, are provided, to give different speeds.
To the legs is screwed a plate 00, which supports the lower side of the plate PP. This receives the ends of the screws SS by which the instrument is levelled, its annular portion being larger than the collar in 00, so that, until clamped by the screwed plate above it, the whole of the instrument except the legs can be moved horizontally in any direction to the extent of about in.
The upper plate is bored through the centre and carries a conical pillar, which rotates freely in it and supports a horizontal plate, to the extreme ends of which are attached, by means of capstan screws or otherwise, two vertical supports, on which the telescope, which is constructed to be perpendicular to the vertical axis of the instrument, rests and rotates with it.
In Japan, Germany, Austria, England and Russia horizontal pendulums of the von Rebeur-Paschwitz type are employed, which by means of levelling screws are usually adjusted to have a natural period or double swing of from 15 to 30 seconds.
The adjustment of the instrument is effected by means of screws in the bed-plate, by turning which the axis o'o" may be brought into a position nearly vertical.
In miscellaneous metal trades, embracing tinplate goods, wire workers, makers of stoves, grates, ranges and fire-arms, makers of bolts, nuts, rivets, screws and staples, and those occupied in several subsidiary trades, the number of operatives in 1901 amounted to 13,209.
The base plate rests upon levelling screws which permit the adjustment of the polar axis to be made with great precision.
This cone is mounted on a circular base b which rests on three levelling screws, two of which are visible in the figure.
Ball's paper on the Theory of Screws, published in 1872.
Balls Theory of Screws an analysis is made of the possible displacements of a b~dy which has respectively two, three, four, five degrees of freedom.
"Smack at 'em, lads!" he kept saying, seizing the guns by the wheels and working the screws himself.
Motion is communicated to the forks by female screws tapped in the heads m and n acting on the screws o and p respectively.
Thus the smallest rotation of either head communicates to the corresponding slide motion, which, if the screws are accurate, is proportional to the amount through which the head is turned.