66 
PLASTER OF CROTON OIL. 
The thinnest plate may receive this preparation without 
becoming brittle, and may thus be turned to account in roof- 
ing buildings. 
The committee wished to ascertain that cast iron, and 
bullets in particular, might be zinced. This application 
must excite the attention of the ministers of war and ma- 
rine, especially the latter, for bullets are so rapidly altered 
at sea, that their dimensions are very soon modified to an 
extent injurious both to the justness of the tier, and the du- 
ration of the pieces. The committee laid a zinced bullet on 
the table of the Academy. 
The Chemist. 
ART. XVI. — PLASTER OF CROTON OIL. 
By M. Bouchard at. 
Croton oil acts as a valuable repulsive in many cases. 
Applied to the skin, it produces a very considerable vascu- 
lar eruption, but much less painful than that of the pustules 
caused by the employment of stibial tartar under the form 
of frictions. It is usually prescribed pure, or mixed with 
oil of sweet almonds. This means of administration is in- 
convenient ; for crotonic acid, the active principle of the 
oil, is volatile, and is often dissipated without producing 
any effect, or else causes inflammation of the skin of the 
fingers used in rubbing. To avoid these inconveniences, 
M. Bouchardat prepares croton oil in the following man- 
ner : — 
He melts, on a gentle fire, 80 grammes of diachylon plas- 
ter, and mixes with this semifluid plaster, 20 grammes of 
croton oil ; he then spreads the plastic mass on calico, so 
