75. Sciopticon Kaleidoscope, with Chromatrope $20 00 



This is an improved arrangement ; the position of light 

 is not changed; it screws into the flange in place of the 

 Objective. 



76. Sciopticon Megascope, for either oil or lime light; easily 



attached in most advantageous position (see Manual, 



p. 193) 5 00 



77. Polar iscope (see Manual, p. 199, Fig. 57) 6000 



COMBINATIONS AND ESTIMATES. 



78. Oxygen Bag, etc., No. 17 ; Retort, etc., No. 20 ; a dozen oxy- 



gen charges, No. 31; four 2%-inch lime wheels, in patent 

 canister, No. 34 ; a dozen feet of tubing, No. 30 3000 



79. Gas Sciopticon ^o. 11, with bag, etc., No. 78 7700 



This is complete for concentric jet where house gas is 

 within reach. 

 With Alcohol Fountain, etc 8000 



80. Same as No. 79, with hydrogen bag No. IS 9500 



This is complete for either concentric or mixed jet, 

 where the hydrogen bag can be filled from the house gas 

 burner. Some timid exhibitors use the concentric jet in 

 connection with a slight pressure on the hydrogen bag, 

 instead of the mixed jet with equal pressure on both 

 bags ; but the mixed jet is unquestionably" enough better, 

 and more saving of gas, to give it the preference, when 

 means for its production are at hand. 



81. Same as No. 80, but with the hydrogen generator No. 25 and 



ten pounds of scrap or granulated zinc 100 00 



82. Gas Sciopticon No. 10, with condensing gas cylinder for 



oxygen No. 27; a dozen oxygen charges; 4 limes; 12 feet 



of tubing 100 00 



This No. 82 effects the same as No. 79 (see Manual, p. 181, 

 Fig. 49) 



83. Gas Sciopticon No. 11, with ^ pair of self-condensing cylin- 



ders No. 29, a dozen oxygen charges, four limes, six feet of 



tubing and ten pounds of scrap zinc 150 00 



Either 81 or 83 is complete for the concentric or the 

 mixed jet. The cylinders, if in perfect condition, are evi- 

 dently the most convenient, and persons accustomed to 

 their use would not willingly do without them; ques- 

 tions, however, as to their continuous reliability and 

 enduring safety are still in dispute among experts, and in 

 common with cylinders charged by the forcing pump, 

 there is still some difficulty in using them in connection 

 with dissolving views. 



