Spectrometers and Accessories #Cat. No. L4020 LABORATORY SPECTROMETER.# This instrument is very rigid and accurate in construction and every part of its design has been carefully considered. The circle has a diameter of 15 cm. and the two verniers read to 20 sec. It is fitted with protecting plate which adds greatly to the value of the instrument if put in the hands of students. The graduation is on solid silver. The verniers are fitted with adjustable magnifying glasses, the telescopes have an aperture of 25 mm., focal length of 200 mm. A horizontal adjustment for the telescope is provided. No provision is made for radial adjustment, which correction is made before the instrument is sent out. The slit is accurately constructed; the jaws are of German silver and it is provided with comparison prism. The eye end of the observing telescope is of standard size so as to receive our micrometers M201 or M202, or the Auto Collimating eye piece (Lamont & Abbe) M540. Gauze eye piece is fitted to the instrument. The prism table and observing telescope have independent movements and each is provided with clamp and tangent screw. The prism table can be clamped to any part of the vernier plate. The prism holder has convenient leveling arrangement and will hold prism up to 35 mm. in height. The instrument is arranged to receive Fuess centering apparatus and crystal holder. A 60 degree heavy flint glass prism of best optical quality is included. Price $75.00 #L4020b CAMERA ATTACHMENT# will fit in place of the observing telescope. It is fitted with long focus objective and standard plate holder 2 1/2"x 2 1/2". The plate holder is provided with swivel for proper focusing of the spectrum. The slit is so arranged that four exposures can be made on one plate. Price $20.00 #Cat. No. L4020c SCALE TUBE.# The third arm of the instrument can be easily attached and rotated and clamped in any position. It may also be used for holding a second Collimator. Price $20.00 #Cat. No. L4021 STUDENT'S SPECTROMETER.# This instrument is in every respect similar to our L4020, but some of the higher finish has been omitted. All the essentials are carefully constructed and the optical parts are of the best quality. The circle is protected but only one vernier reading to 30 sec. is fitted to the instrument. The magnifying glass is omitted. Price, including prism $60.00 [Illustration] [Illustration] TRANSCRIBERS' NOTES General: Corrections to punctuation have not been individually noted. General: Inconsistent spelling of catalog/catalogue preserved as in original. Page 7: magnifiing corrected to magnifying and celestrial corrected to celestial. Page 17: intensisy corrected to intensity.