American Journal of Science. 7 



Philosophical Instruments, Manufactured and Sold 



BY N. B. & D. CHAMBERLAIN, 



Nos. 2 and 9 School Street, Boston. 



Attwood's Machines, with Second Clocks, Weights, &c. com- 

 plete, ei2[ht feet high, $25, $50, and $100. Tables with Spring 



#6. Wh 



$35 



$25 



$25, $40, and $ 



Hydrostatic Presses, Hydrostatic Bellows, Hydrostatic Paradox, 

 Glass Barrel Lifting Pump, and Improved Forcing Pump, and 

 Stand, with Cisterns, Hose, &c. 



Air Pumps, all worked with the Simple Lever. 



No. 1, eight inch plate, barrel 7 by 2i inches, $25. No. 2, 

 eight inch plate, two barrels 7 by 2} inches, $35. No. 3, twelve 

 inch plate, barrel 11 by 3£ inches, has a barometer gauge, $75. 

 No. 4, # thirteen inch plate, barrel 13 by 4 inches, $125. No. 5, 

 fifteen inch plate, barrel 13 by 4J inches, $150. 



Bell Glasses are fitted to all the different pumps, from half pint 

 to fourteen gallons. Prices from 25 cts. to $12. 



Electric Machines. — Sixteen inch plates with two conductors, 

 well proportioned and finished, $25. Twenty four irrch plate, with 

 two conductors, $40. Twenty eight inch plate, two conductors, 

 $50 to $60. Thirty inch plate, two conductors, $75. Thirty 

 six inch plate, two conductors, $85. Forty inch plate, two con- 

 ductors, $125 to $150. Fifty five inch plate, two negative con- 

 ductors, two pair rubbers, prime conductor 7 feet by 8 inches, 

 $400. All the usual varieties of apparatus accompanying the above 

 machines, at fair prices. ^ 



Chemicals. — Cylindrical Gasometers, with Webster's Improved 

 Compound Blowpipe, Cisterns with Gas Holders, Retorts for Oxy- 

 gen, Lamp Stands, Gas Bags, Pyrometers, &c, Chemical Glass, 



all sizes and varieties. 



Galvanic and Electro-Magnetic Apparatus. 



Working Models of Steam Engines,. $35, $60, to $100. Sec- 

 tion Models of Steam Engines, $12 to $18. 



Astronomicals. — Orreries, Season Machines, Tide Dials, Globes. 



For further and more particular information, see Catalogues, 

 which will be furnished on application. 



Boston, March 11, 1842. 



* One of pump No. 4 is in use by Dr. Webster, Harvard University, one by 

 Prof. Lovering, Harvard University, one by Prof. Olmsted, Yale College, one by 

 Prof. Young, Dartmouth College, one by Prof. Hopkins, Williams College, one by 

 Prof, Whipple, Oberlin Collegiate Institute, several of No. 3, and some thirty are 

 now in use in academies in the United States. 



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