{ 206 J 
Read July 10th, 1816. 
Si, ) 
The following contains a confirmation of the opinion 
I have always held, as to the operative principle of the 
plaister of Paris. It will be seen in my “agricultural 
inguiries on plaister of Paris,’ published in 1797, that 
I therein mentioned, asa conjecture, what reiterated 
experiment has since proved. I translate from the 
French, a sketch of the memoire on the subject, sent 
to me by a friend. It contains information worthy of 
being promulgated ; though much of it is here, more 
confirmatory than new, as to the plaister. But I do not 
recollect that any experiments have been made with 
SULPHUR, for the purposes stated in the memoire. 
Ricuarp PETERS. 
20th June, 1810. 
Dr. James MEASE. 
Secretary of the Agric. Soc. Philad. 
THE EFFICACY OF SULPHUR ON VEGETATION. 
“4 memoire of M. Berarp the elder a trader at 
PONT-LIEU LES LE MANS, and member of the society 
of that town, treating on the use of PLAISTER or GYP- 
sum, employed as a manure; containing observations 
curious and useful in agriculture.” 
“Mf. Berard observed, with admiration, in many jour- 
nies on the borders of the lake of Geneva, in Savoy, 
