CENTRAL SCIENTIFIC CO., CHICAGO, U. S. A. 



No. 881. 



881. BAROMETER, Aneroid. Brass case, 5 inches in diameter; open 



porcelain dial; visible works. Graduated to 0.02 inches.... $11.00 



882. BAROMETER, Aneroid, 4-inch card dial, open face, nickel-plated 



case. Graduations in both English and metric systems. For alti- 

 tudes up to 3,000 feet. Without altitude scale 6.00 



890A. BAROMETER, Mercurial, Cenco Improved, Fortin Principle. Has 

 straight glass tube of heavy wall and uniform bore mounted in a 

 hexagonal brass protecting case, and is provided with a screw ad- 

 justment for changing the level of the mercury in the cistern. The 

 scales are readable by means of a vernier to 1/10 mm and 1/200 

 inch. The lowest possible reading is 23 inches (63.5 cm), so that 

 the barometer is not satisfactory for altitudes above 4,000 feet. 

 (See No. 891A for a high altitude barometer.) Complete with 

 thermometer having both a Centigrade and Fahrenheit scale . 25.00 



891A. BAROMETER, Mercurial, Cenco. Same as No. 890A, but with a scale 

 reading down to 20 inches. For use in altitudes up to 10,000 

 feet 27.50 



894. BAROMETER, Standard Mercurial, United Statss Weather Bureau 

 Type, Fortin Principle. This barometer is of the highest type of 

 No. 890A. excellence, indorsed by the United States Weather Bureau and 



fully warranted by the manufacturer. The mercury tube 

 is inclosed in a brass body with gun-metal finish, having at its 

 upper end two vertical openings, in which the vernier works, the 

 latter operated by a rack and pinion movement. The readings are 

 taken through these openings, aided by light reflected from a white opaque 

 glass reflector attached to the board behind. The scale is graduated on one 

 side in inches and lOths, and on the other in centimeters and millimeters, the 

 vernier enabling a reading to be taken, in each case respectively, of one- 

 thousandth of an inch and one-tenth of a millimeter. The attached ther- 

 mometer consists of a well seasoned tube with both Centigrade and Fahren- 

 heit scales, with the figures etched on the stem. It is so mounted that it 

 can easily be removed for testing, etc. Beads down to 25% inches and is 

 therefore not satisfactory for altitudes above 3,500 feet. 



Complete with board back of finely finished hardwood, to which is attached a 

 brass bracket to receive the ring in the top of the barometer, a ring with 

 steadying screws to clamp about the cistern, and white opaque glass reflectors 

 forming a translucent background for reading the instrument 65.00 



No. 894. 



