424 



CENTRAL SCIENTIFIC CO., CHICAGO, TJ. 8. A. 



NO. 11208. 

 ELECTROSCOPE HEAD, Continued. 



No. 11203 with No. 11200 mounted on it. 



11201. 



11202. 



11203. 

 11204. 



11205. 

 11206. 

 11207. 



11208. 



11209. 

 11210. 

 11211. 



The Microscope, magnification, 24-fold; focal distance 32 mm, is carried by a projecting soliil 

 front, and is very firmly fixed with relation to the leaf. It may be refocused, however, by 

 releasing a split collar controlled by a heavy milled-head screw. The microscope has a gradu- 

 ated and numbered micrometer scale in the eye-piece by which the motion of the leaf is 

 measured. 



The Head as a whole comprises a very compact readily transportable unit, and yet one that can 

 be easily taken apart if it is desired to do so. Complete as described $63.00 



OPEN DISCHARGE CHAMBER FOR SOLIDS, a cylinder for use with Head No. 11200, 10.5 

 cm high, 9 cm in diameter, with a door 5 cm high, and 9 cm broad. The plate electrode is 

 5.5 cm in diameter and is supported horizontally at 1.5 cm below the tep of the chamber, by 

 a rod that passes up through an amberoid insulator, and terminates in a cap to fit the inter- 

 changeable top. The chamber is provided with a friction cap to protect the insulator when 

 not in use 15.00 



GAS-TIGHT EMANATION CHAMBER, for use with Head No. 11200, 10.5 cm high, 9 cm in 

 diameter, provided with two special gas-tight stop-cocks. Volume, about % liter. The am- 

 beroid insulation is made gas-tight by a special mechanical joint without any wax or other 

 binding material. Since each emanation chapiber can be used only once daily, as many dupli- 

 cates must be provided as it is desired to make daily determinations, all being used with one 

 top. At least one extra Charging Cap No. 11210 is needed with more than one chamber. 18.75 



LIGHT WALLED WATER CHAMBER, height, 13 inches; diameter, 10 inches; weight, 4 

 pounds; capacity, about 4 gallons. Intended especially for field use with Head No. 11200, 

 where water is introduced directly into the chambers. Amberoid insulation, stop-cock outlet 

 above, and large opening below, with rubber stopper for introduction of water 15.00 



HEAVY WALLED WATER CHAMBER, for use with Head No. 11200. Height, 13 inches; 

 diameter, 10 inches; weight, 13 pounds; capacity, about 4 gallons. Intended for laboratory 

 use, the walls being rigid enough to support a complete vacuum for the boiling-off method. 

 Water can also be introduced directly if desired. Price quoted upon application. 



PLATE FOR SOLIDS, 5.5 cm in diameter with narrow rim 2 mm deep, to be used with No. 

 11201. At least two, and probably more, are desirable each 1.25 



CHARGING ROD, a tapering rod of hard rubber 8 inches long, for charging in field work and 

 where battery is not available -50 



BATTERY SET, consisting of dry cells connected in series, in covered wooden box, with insu- 

 lated wire to guard one end of battery, charging wire with floating terminal and knife 

 switch to protect whole. Dimensions of box, 18x15x6 inches 43.00 



GAS BURETTES FOR EMANATION, a glass burette with one capillary two-way stop-cock 

 above and one wide-bore cock below. Length of burette, 60 cm; diameter, 3 cm; length over 

 all, 80 cm. Two are desirable for rapid work each 10.00 



MICRO-DRYING BULBS for Sulphuric Acid, to be used between Nos. 11202 and 11208 in 

 transferring gases. One is needed for each gas burette 1-50 



CHARGING CAP, of hard rubber with binding post, to be used in maintaining charge on No. 

 11202 when Head No. 11200 is in use 1.50 



HAND PUMP, Vacuum or Pressure, of special construction for use in evacuating No. 11202 

 Chamber . 10.00 



