588 Proceedings of the Royal Society 
Figs. 4, 5, and 6 show the waves given by the sound “ oh f spoken at 
Fig. 6. 
various pitches by the same voice (that of Dr Crum Brown). Figs. 
Fig. 7. 
Fig. 8. 
7 and 8 are given by the sound a in “ father,” the first on c by Sir 
B. Christison, the second on c' by Professor Jenkin. 
3. On the Action of the Chlorides of Iodine upon Acetylene 
and Ethylene. By George M‘Gowan. 
Before giving the action of ethylene on the chlorides of iodine, I 
may shortly describe the method of preparing the latter, which I 
found to he the most advantageous : — 
A weighed quantity of perfectly dry iodine being introduced into 
