232 
Proceedings of the Boyal Society 
the effect on man. One of themselves, accordingly, took, on one 
occasion, half a grain of iodide of methyl-morphium as a powder, 
and on another, one grain (containing about three-fourths of a grain 
of morphia), but on neither occasion was there observed the slightest 
soporific or other effect. 
Four grains of sulphate of methyl-morphium produced decided 
narcotism on a rabbit, but no convulsive effect. Indeed, with this 
dose, and with various others that were given, paralysis appeared, 
and the authors have demonstrated that this symptom is due to an 
effect on the motor nerve end-organs. 
Iodide of methyl-nicotium was obtained in the form of crystals 
extremely soluble in cold water. When given to rabbits by subcu- 
taneous injection, a dose of five grains was perfectly inert ; one of 
fifteen grains produced serious symptoms, followed by recovery : and 
a dose of twenty grains was fatal. The symptoms were principally 
distinguished from those of nicotia by the absence of convulsions ; 
but no paralytic action on motor nerve end-organs was caused. 
The authors have also investigated the action of iodide of 
methyl, andjhey obtained no evidence in support of the extremely 
improbable hypothesis, that some of the changes produced in the 
action of the substances they had examined might have been due 
to the addition of the physiological action of the methyl compounds. 
They conclude by discussing the possible causes of these modifica- 
tions, by pointing out some of the practical applications of their 
results, and by promising to examine how far iodide of methyl may 
prove an antidote to the poisonous effects of these vegetable alka- 
loids, whose fatal dose it increases. 
2. On the Burning Mirrors of Archimedes, and on the Con- 
centration of Light produced by Reflectors. By John 
Scott, Esq. Communicated by Professor Kelland. 
That the Roman ships were destroyed by burning glasses in- 
vented by Archimedes, is mentioned as a fact by most of the ancient 
writers, especially those who treat on mechanics, and their state- 
ments have been repeated by succeeding authors, without any 
