We use Optical Character Recognition (OCR) during our scanning and processing workflow to make the content of each page searchable. You can view the automatically generated text below as well as copy and paste individual pieces of text to quote in your own work.
Text recognition is never 100% accurate. Many parts of the scanned page may not be reflected in the OCR text output, including: images, page layout, certain fonts or handwriting.
Bausch & Lomb Optical Company Model B Balopticon Figure 1—Model B with Mazda Lamp and 2%6-Inch Diameter Lens. This compact, efficient little instrument met with instant success when placed on the market and is now one of the most popular projection lanterns in its class. It meets the growing demand for a really high grade stereopticon at a moderate price and is designed for use with lantern slides only in class rooms, Sunday schools and the home. It is a great favorite with the amateur photographer. He can easily make slides for it from his negatives, or with attachments he can use it effectively as an enlarging lantern for negatives up to 3 Y\ x 4 % inches. We equip this model with either the 250-watt, gas-filled Mazda lamp, or with the small arc lamp and 4j4-ampere rheostat, where electricity is available. On account of its high efficiency and simplicity of operation, the former type of illuminant is usually preferred. It equals the illumination given by the 5-ampere arc lamp, yet consumes only iVz amperes of current and is entirely automatic. Where electricity is not available, a double-jet acetylene burner is used with a special spherical mirror. The same style of lamp house is used with both the acetylene burner and the Mazda lamp (Figure 1). Special features of this lantern are : the method of ventilating both lamp house and condenser mount, permitting the use of lantern slide films if desired without the expense and inconvenience of a water cell; the extreme compactness and light weight, which make it a very desirable equipment for traveling lecturers or salesmen who use lantern slides in demonstrating their lines. Specifications Base —Consists of front and rear metal standards carried on sliding rods. Lamp House —Of sheet metal with special ventilation; two styles—one for arc lamp measuring 6/4 x 214 x 5 in., and that for Mazda or acetylene lamp measuring 6}4 x 7 x 5 in.; both styles fit in grooves to rear standard and can be instantly interchanged by lifting out one and sliding in the other. Illuminant —Our 250-watt, gas-filled, Mazda stereopticon lamp, Adjustable Baby Arc Lamp with small 4/4-ampere rheostat, or double-jet acetylene burner with mirror, as desired; carbons of arc lamp can be adjusted independently and then easily fed forward by turning a single convenient button. Condensing System —Our regular double system, 4/4-in. diameter, in special ventilated mount from which lenses can be easily removed for cleaning. * Slide Carrier —Our double carrier, No. 4430, with elevating device. Bellows —Mounted on metal frames which slide in m et al ways. *The quick changing slide carrier, No. 4449, giving a dissolving effect, may be substi- tuted for $1.50 extra. We can supply to order carriers for small slides, so that one may use either the standard slide or the special small size now being offered. 21