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Bausch & Lomb 1908 catalog of Engineering Instruments


Standard 5 inch Transit

This is undoubtedly the most popular size of transit offered, and the original features of our product combine to make it a very desirable instrument for general work. It is equally well suited to the requirements of the mining engineer and the surveyor. All constructive details are of superior design and unexcelled workmanship. While great stiffness is given to the instrument, unnecessary weight is avoided, the standard rib construction being employed. The free aperture of the telescope is very large, and is fully utilized, giving a brilliant field well defined and free from distortion. The optical parts are carefully selected, and are accurately centered with respect to the axis of the telescope tube.

The telescope is erecting and is provided with our patented variable power eyepiece, as described on page 9. However, if desired, an inverting telescope will be furnished. The axis carries on top a center mark exactly over the vertical axis, hence this mark is in the center of the instrument when the instrument is level and the telescope horizontal.

The variation plate is continuous and the plate levels are fully protected, being mounted inside the compass box. Extraneous levels for mining work are furnished when desired.

The graduations may be had in a variety of styles, as illustrated on page 11. They are of extreme accuracy and are well engraved, so that readings may readily be made without fatiguing the eyes. The reading is to single minutes by double opposite verniers provided with ground-glass shades.

A vertical arc with vernier adjustable laterally by two screws is also regularly supplied on this instrument. While adjusting, the vernier describes a circle which is concentric with the vertical arc or circle, thus maintaining the correct relative position.

Other Specifications

The horizontal circle is 5 1/2" in diameter, measured inside the graduations, and 6 1/2" outside. The graduations of the circle read to single minutes by double opposite verniers. The vertical arc is 5" in diameter, and also reads to single minutes by one double vernier. The compass needle (see page 9) is 3 7/8" in length, with a sapphire center.

When an erecting telescope is furnished, it has the following specifications: length 10", power with variable power eyepiece 16 to 25, effective aperture 1 5/16" and an apparent field of 30 degrees.

If an inverting telescope is desired, we furnish one having the following dimensions: length power 18 or 30 as ordered, effective aperture 1 5/16" apparent field 30 degrees.

The telescope level is 4 1/2" long and is graduated in 2 mm. divisions, each division representing 20" of arc. The plate levels are graduated in the same manner, with a value of about 6o" for each division.

The telescope axis carries a center-point which is exactly over the center when the instrument is leveled up and the telescope is horizontal. The axis is also provided with clamp and tangent screw.

The range of the shifting center is 1/2". The solar attachment is capable of being used as an auxiliary telescope for vertical sighting. The instrument is 11 1/2" high, and weighs about 13 1/2 lbs., in carrying case 23 1/2 lbs., and when ready to ship 37 lbs. The ordinary tripod weighs 8 3/4 lbs., and 23 lbs. when ready to ship. The approximate weights of the extension tripod are 10 lbs., and 24 1/4 lbs. when packed.

Cat. DESCRIPTION Price
40 Complete Standard 5" Transit, as specified and as illustrated on page 30, including the variable power eyepiece and the vertical arc adjustable by fine tangent screw, and the position of the vernier controlled by a sensitive level attached to the arm carrying the vernier, and split-leg tripod . . . . . . 250.00
42 Standard 5" Transit. with variable power eyepiece and full vertical circle 5" in diameter, with a metal cover guard and reading to single minutes by two double opposite verniers attached to the cover guard (see illustration page 24), with split-leg tripod 245.00
44 Standard 5" Transit, with variable power eyepiece and with the full vertical circle with guard, read by one double vernier placed between the standards, as illustrated on page 26. and including split-leg tripod . . . . . . . . 235.00
46 Standard 5" Transit, with vertical arc and variable power eye piece. as illustrated on page 21, with split-leg tripod . . 225.00
48 Standard 5" Transit, as described and specified, but without vertical arc, including variable power eyepiece and with split-leg tripod . . . . . . . . . . 210.00

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