But the wind slides eastward over its opaque surface in vain, till it reaches the living surface beyond.
The highway department would periodically close the road and, using explosive devices, create slides in a controlled condition, lessening the chance for a surprising and perhaps deadly run loosed by nature on the unsuspecting below.
While back-country skiing was also popular, the ever constant danger of killing snow slides made marked trails a safer method of enjoying this vigorous sport.
These slides are shown in fig.
The slides are accurately fitted so as to have no sensible lateral shake, but yet so as to move easily in the direction of the greatest length of the micrometer box.
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.
In this micrometer the three slides moved by S, s, and s' are simple dovetails.
The lowest of these slides reposes upon a foundation-plate pp, into one end of which the screw s is tapped.
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.
All the essential parts of the micrometer, including the slides, micrometer box, tube, etc., are of steel or cast-iron, so that changes of temperature do not affect the adjustments.
Owing to their want of adhesiveness, they are, however, usually mounted on glass as microscopic slides, either in glycerin jelly, Canada balsam or some other suitable medium.
The test bar C C, which slides through holes bored in the yoke, is divided near the middle into two parts, the ends which come into contact being faced true and square.
One of the few uses of crown-glass of this kind is the glass slides upon which microscopic specimens are mounted, as well as the thin glass slips with which such preparations are covered.
This head slides freely in the cast iron tubes, and is connected by a copper rod with one of the terminals of the dynamo supplying the current.
The slides carrying the segments of the divided object-glass are mounted on a plate, which is fitted and ground to rotate ...
The slides are moved by the screws a and b, the divided heads of which serve to measure the separation of the segments.
The reading micrometers e, f also serve to measure, independently, the separation of the segments, by scales attached to the slides; such measurements can be employed as a check on those made by the screws.
On the other hand it is not necessary to reset the telescope after each reversal of the segments.4 When Bessel ordered the Konigsberg heliometer, he was anxious to have the segments made to move in cylindrical slides, of which the radius should be equal to the focal length of the object-glass.
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.
Modern heliometers made with cylindrical slides measure angles over 2°, the images remaining as sharp and perfect as when the smallest angles are measured.
It permits complete rotation of the tube and measurement of all angles in reversed positions of the circle; the handles that move the slides can be brought down to the eye-end, inside the tube, and consequently made to rotate with it; and the position circle may be placed at the end of the cradle next the eyeend where it is convenient of access.
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.
The screw, turned by the wheels at g', acts in a toothed arc, whence, as shown in the figure, equal and opposite motion is communicated to the slides by the jointed rods v, v.
The slides are kept firmly down to their bearings by the rollers r, r, r, r, attached to axes which are, in the middle, very strong springs.
The mounting, the tube, objective-cell, slides, &c., are all of steel.'
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 prism p is fitted accurately into brass slides (care has to be taken in the construction to place the prism so that an object in the centre of the field will so remain when the eye-piece is rotated in its adapter).
As soon as a hot billet A is withdrawn by pushing it endwise out of the exit door B, the whole row is pushed forward by a set of mechanical pushers C, the billets sliding on the raised water-cooled pipes D, and, in the hotter part of the furnace, on the magnesite bricks E, on which iron slides easily when red-hot.
On the 9th the admiral received a report that working parties had been seen in Fort Silsileh parbuckling two smoothbore gunsapparently 32-pounderstowards their respective carriages and slides, which were facing in the direction of the harbour.
The rods BC and DB carry two small rods EF, GF jointed at F; at this joint there is a pin which slides in a slot on the rod BH, which is normal to the mirror X.
It is utilized in the spindles of machinetools, in the balls and rollers for high-speed bearings, slides, pivots and such like.
The air is distributed by means of wood air trunks with openings controlled by slides, and similar trunks are pro vided in connexion with the suction of the compresser to conduct the air back to the machine.
The air cooler is placed at the end, and the air is distributed by means of wood ducts furnished with slides for regulating the temperature of the rooms, which are insulated according to the method shown in fig.
A cross-table is very convenient for this calculation, for with the aid of the two movable slides situated in the plane of the plate and at right angles to one another, the point where the two crystal edges intersect can be quickly and correctly brought into the revolving axis of the plate.
If less, A slides over B, the rate of motion being determined by the excess of the effort over the resistance (friction).
Underneath the top plate of the machine, and strongly framed to it, is a box, which contains the horizontal rods to the ends of which are attached the slides which regu late the flow of sugar from the 8 bottom of the hopper.
The platen was screwed on to the under surface of the spindle; the table or bed had slides underneath which moved in, and not on, ribs as in the older form of press, and was run in and out by means of strips of webbing fastened to each end and passed round a drum or wheel.
Now let PT be a tangent to the curve at P, cutting OX in T; PT=PYXsecant obliquity, and this is to be a constant quantity; hence the curve is that known as the tractory of the straight line OX, in which PT = OR = constant, This curve is described by having a fixed straight edge parallel to OX, along which slides a slider carrying a pin whose centre is T.
Shifting in a straight line is regulated either by straight fixed guides, in contact with which the moving piece slides, or by combinations of link-work, called parallel motions, which will be described in the sequel.
In any displacement about 0 as a fixed point, the former sphere slides over the latter, as in a ball-and-socket joint.
Again, the normal pressure between two surfaces disappears from the equation, provided the displacements be such that one of these surfaces merely slides relatively to the other.
As a simple example, take the case of a light frame, whose bars form the slides of a rhombus ABCD with the diagonal BD, suspended from A and carrying a weight W at C; and let it be required to find the stress in BD.