108 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 65 



All free balloons were started at Avalon, Santa Catalina Island, Cal. 

 Because of the possibility of the instrument coming down in the ocean, 

 balloons were sent up in pairs and with a float. This float weighed approxi- 

 mately 450 grams. Each balloon was filled until it would lift decidedly 

 everything to be sent up except the float The balloons were then attached 

 to the system in such a way that when either of them burst it would detach 

 itself from the system, which then sank to the earth's surface with the 

 remaining balloon. This device by which the balloons are connected with 



Fig. 1. — Device for releasing burst balloon. 



the system and which serves the purpose of releasing the burst balloon is 

 shown in figure 1. It is made of spring brass wire of approximately 2.4 mm. 

 diameter. The pressure of the springs B and C on the wire A at the points 

 D and E is sufficient to prevent the rings from slipping off in case cord F or G 

 becomes slack. The weight of the burst balloon or of what is left of it slips 

 the ring off easily. Cords F and G must be so short that they will not twist 

 above the device. 



The balloons used were of thick rubber, similar to those used at Huron in 

 the early autumn of 1910 and at Fort Omaha in the late winter of 191 1, but 

 not so large. They were filled with electrolytic hydrogen which had been 

 compressed in steel cylinders. 



