STANDARD - Survey Instrument Antique Center!

249
NOTES TO THE PRECEDING LIST OF ARTICLES
SUPPLIED BY MAIL.
A. Concerning Tangent and Leveling- Screws.
Tangent and leveling screws can only be made to fit as nearly as possible without having the instrument in our
shop. Both kinds are micrometer screws, made with great care and fitted to the particular instrument, and, therefore,
are not interchangeable. When possible the tangent piece or bracket, or in the case of a leveling screw the whole
leveling head should be sent us, so that we can fit it properly.
If for instance the tangent screw sent you in the absence of the tangent piece or bracket should fit too
tightly and you have nobody to fit it, then if you can wait, unscrew the tangent piece and send it to us by registered
mail. Make sure to replace each small screw into its screw hole in the plate. If the screws are transposed
they may project through, touching the circle and injuring it.
If you have an instrument repairer in your vicinity, he can fit the screw by working it in and out in its nut
with a little tallow until it works freely, then in the temperate or frigid zone the tallow must be removed from the
screw and female thread by using a little benzine on a rag wrapped around a stick. When free from -tallow a little
watch oil or vaseline should be applied as a lubricant. A jeweler or optician should be able to do this.
Under no circumstances should, aay emery be used on one of these screws, as this would spoil it for
ever. If nat successful the entire tangent piece and the screw should be sent us by registered mail, as already
mentioned.
A-:VOTKIK. Tripod head.
When a new tripod head is required for an instrument having four leveling screws on account of its being
bent, or the screw threads worn too loose, then generally a new lower foot-plate to leveling head (see list above)
and a new packing piece to screw instrument to the slide board in box will be needed also.
I
49-NOTEC. Tripod bolts, nuts, washers, clamps and shoes.
Send us an outline sketch on paper obtained by running a sharp pointed pencil closely around the article
desired.
3-NOTJ2 . Tripod legs.
As the extension tripod legs and clamps vary in size and have been changed in style from those formerly supplied,
it will be necessary to denote the size by sending the outline obtained as in Note C.
*-;VOTKK.
Glass shades, vernier glasses and shade frame.
Send the broken pieces or an outline sketch as described in Note C. If the vernier glasses, etc., sent are too large
a local optician may grind them to size. If too loose the frame should be narrowed at the top.
49-NOTEF. Magnetic needle.
When a new needle seems to be required on account of loss of magnetism, the trouble is usually that the point
of the pivot is dull and then needs to be carefully sharpened to a fine point or that the Jewel
cap may have It -come rougn or rusty and needs to be polished .%. very little magnetism is
required to make the needle work satisfactorily when the pivot point is sharp and the cap well polished.
To preserve the sharpness of the pivot It Is necessary to use great care In lowering the
needle onto the center point, since it may be dulled the first time it is used if the needle is
dropped carelessly upon its pivot.
49-rvoTE G. Clamp screws to the telescope's axis.
Only an ordinary regular telescope clamp screw can be supplied. All transits provided with a striding level
or a solar attachment require a clamp screw especially made with head of smaller diameter to enable the passage
of these features around the head of the clamp screw when the telescope is revolved on its horizontal axis. A
sketch with the size and length of head is to accompany the order.
49-NOTEH. Object glass and Eye-piece.
Sometimes it happens that an object glass is slightly warped by the excessive heat of summer, shown by a
distortion of the image, making it impossible to obtain a sharp, well Defined image, or that the extreme cold of
winter may crack the balsam (see description of the telescope page 31 N with which the lenses are cemented together,
shown by numerous streaks or stars. (A few such streaks or stars are not hurtful, since they cut out
only a very small amount of light.) Such an object glass should be sent to us for recementing. Then, in most
cases, a new cell is also needed in which to mount it again which adds to the cost of repairing.
In every permissib'e case the entire telescope should be sent us. After the object glass or telescope is returned
to the sender it it neeesiary to readjust the cross wires for coiiimatlon as explained under "Adjustments"
on page 54 of catalog.
49-NOTEi.
Stadia wires.
Stadia wires must be fitted specially to the focal length of each object glass, and therefore, we should receive
the entire te.lescope If possible, or at least ihe object glaan, and it will also b well to atato
whether the telescope is erect or inverting, a* otherwise w can only furnish the wires approximately
correct.
When a new object glass is required, now stadia wires as a rule must be supplied also.