OF ARTS AND SCIENCES. 61 



YI. 



CONTRIBUTIONS FROM TOE CHEMICAL LABORATORY OF 



HARVARD COLLEGE. 



ON THE VAPOR-DENSITY OF TtlE CHLORIDE, THE 

 BROMIDE, AND THE IODIDE OF ANTIMONY. 



Bt C. p. Worcester, A. B. Harv, 1883. 

 Presented May 9th, 1883. 



The usual form of the tube employed in Victor Meyer's method for 

 determining vapor-densities was found unsatisfactory, in that any slight 

 variation in the tension or the temperature of the enclosed air — such 

 as was caused by drawing out the stopper or dropping in the sub- 

 stance — was apt to draw water up the delivery arm from the pneu- 

 matic trough, and so crack the hot tube. This was remedied by 

 enlarging the delivery arm both in length and in bore. Several modi- 

 fications of the tube were tried, varying in capacity from 75 to 200 

 cubic centimeters. The tube that was found most satisfactory was of 

 hard glass, of the usual form (with the exception just noted), and of 

 about 150 c.c. capacity. 



The neck was closed with a perforated rubber stopper, into which 

 was fitted a thin glass tube drawn out and closed at one end, the other 

 end being thrust nearly through the bored stopper. The substance 

 was weighed out in a small tube of the same size as that just described, 

 and the open mouth of this weighing tube was thrust into the lower 

 end of the same perforation ; so that the rubber stopper both held and 

 closed it. The stopper being tightly fitted into the neck, and the ap- 

 paratus heated to a constant temperature, the upper tube was forced 

 downwards, pushing before it the tube holding the substance, which 

 was thus dropped into the bulb of the apparatus. As soon as the dis- 

 placed air ceased to come over, the closed tip of the upper tube was 

 broken off, thus effectually preventing the back flow from the pneu- 

 matic trough on cooling the apparatus or drawing the stopper. 



