52 Correspondence. [January, 
arsenic, either in the form of arseniuretted hydrogen, or arse- 
nious oxide, or emerald green have been made ; and until these 
examinations — especially the last — have been made, and the 
results are affirmative, the medical writer must forgive me if I 
remain sceptical as to the poisonous effects of wall-paper when 
stained with Emerald Green. 
Robert Galloway. 
“THUNDERBOLTS AND THUNDERSTONES.” 
The term Thunderstone is not very frequently in use in the 
present day. The term Thunderbolt is very frequently used, 
and is applied to the lightning-flash when there is explosion or a 
crash. I have not heard it applied to any form of iron-pyrites, but 
it is a name very generally given to certain fossil remains found 
in gravels from the chalk, greeensand, oolite, and lias. They are 
of a cylindro-fusiform shape, and are the fossilised pens of cuttle- 
fish (Belemnitidae). Those from the lias, on being fradtured, 
emit a strong sulphurous smell. The material is carbonate of 
lime. 
Henry H. Higgins. 
Rainhill. 
