22 A V O L U M E 19, N O . 9

A. H. T. CO. SPECIFICATION

BURETTE M E N I S C U S READER and THERMOMETER READER

2501. 2501-A. 9632-A.

BURETTE MENISCUS AND THERMOMETER READERS, A.H.T. Co. Specification. With an adjustable hinge which makes it possible to increase or diminish the distance between the clamping arms. Construction of the holder is rigid, but light, being of aluminum finished in dull black.

With focusing lens, improved type of background and quick-acting spring clamp. With the cotter pin inserted in the outside hole of the adjustable hinge, tubes from 6 to 22 mm diameter can be accommodated; with the cotter pin inserted in the inside hole, tubes from 5 to 14 mm diameter can be accommodated.

Three reading attachments are offered, i.e., one for use with regular size burettes, one for use with small burettes, and one for use with thermometers with enclosed scale. All three attachments can be used interchangeably in the holder.

The reading attachment with 4-inch focus lens is intended for observing the position of the meniscus of an aqueous liquid in a burette of regular size, i.e., with diameter of approximately 12 to 18 mm, which is sharply defined as a curved black line against a white field. The depth of focus of the lens is sufficient to permit superposition of lines on the front of a tube with those on the back — on burettes with all-round graduations such as our 2400, etc. — avoiding parallax. Observations can be made with either reflected or transmitted light and the position of the meniscus at a mercury-gas or mercury-water interface can be accurately observed.

The reading attachment for small Burettes consists of a 2-inch focus lens of the same diai.ieter but mounted in a shorter tube than that for regular burettes. I t is suitable for burettes of small diameter such, for example, as Folin Sugar Titra­tion, Micro Burettes, and Koch Automatic Burette with filling tube at the side, but is not intended for use with Automatic Micro or other burettes with filling tube directly behind the graduated tube.

The thermometer reading attachment contains a 2H-mch focus lens and is so mounted that reflections from the surface of the outside tube of an enclosed scale thermometer such, for example, as a Beckmann thermometer, are reduced to a mini­mum. This greatly increases ease and accuracy in reading a thermometer scale graduated in small intervals.

2S01. Burette Meniscus Reader, A.H.T. Co. Specification, as above described, complete with reading attachment with 4-inch focus lens for use with regular size burettes 15.70

2501-A. Ditto, but with reading attachment with 2-inch focus lens for use with small burettes — but not with automatic mic.ro burettes with filling tube in rear 14.90

9632-A. Thermometer Reader, A.H.T. Co. Specification, as above described, with reading attachment with 2J4 inch lens mounted specially for use with an enclosed scale thermometer 15.70

Accessory and Replacement Parts

2502-B. Burette Meniscus Reading Attachment, only, with 4-inch focus lens for use with regular size burettes; for interchangeable use in the holder of above Readers 5.95

2502-C. Ditto, but with 2-inch focus lens for use with small burettes 5.15 2502-D. Thermometer Reading Attachment, only, with 2H inch focus lens for

enclosed scale thermometers; for interchangeable use in the holder of above Readers 5.95

2502-H. Holder, only, as supplied with 2501, 2501-A and 9032-A Readers. . . 9.75

Field of view in burette with all-round graduations, with eye in correct position, i.e., no parallax

on critical line A—B.

Field of view in Beck­mann Thermometer

ARTHUR H. THOMAS COMPANY RETAIL—WHOLESALE—EXPORT

LABORATORY APPARATUS AND REAGENTS WEST WASHINGTON SQUARE, PHILADELPHIA 5, PA., U. S. A.

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