Foreign Literature and Science. 351 
eed on the part rubbed. The use of it is extremely clean- 
ly, and its expense is very much below that of the common 
ointment. For the preparation of this ointment it is essen- 
tial that the lard be entirely free from salt, or else calomel 
will be formed. The oxid may be prepared by decomposing 
calomel by pure potash, or by pouring solution of nitrate 
of mercury into caustic alkaline solution. The fat only dis- 
solves three grains of oxid for each drachm, but the quanti- 
in the ointment, may easily be increased. The oxid 
should be first triturated with a little cold lard, to make the 
penetration complete. The degree of heat is important. 
At 212° the oxid and lard will not combine, at 600° the ox- 
id will be decomposed, and mercury volatilized, at 500° 
and 400° the oxid is partially decomposed, some red oxid 
being formed, and mercury reduced. e best heat is be- 
tween 300° and 320°; it should be maintained at least an 
hour, and the ointment should be stirred till cold. This 
ointment is now undergoing extensive trial, and the results 
are very favourable. Already several testimonies have been 
given by medical men to its value.” Ibid. 
“ Lignite——Mr. Becquerel has examined and published 
an account of a'stratum of fossil wood, occurring at Auteuil, 
in the neighbourhood of Paris, which seems of great extent. 
It contains, interspersed here and there, succinite, and crys- 
tals, supposed to be of mellite, but the exact nature of which 
has not been ascertained.” “This stratum of lignite con- 
tains trees, still entire in their forms, some of considerable 
length, and varying in diameter from six to eighteen inch- 
es,” Ibid. 
Extract of a letter from Dr. Daubeny, of Oxford, ( Eng- 
land,)* to his friend in this country. 
_ “T spent three months,” says he, “in Auvergne and the 
Vivarais, and am returned, quite convinced of the igneous 
origin of the whole of that interesting country. In some 
Places, the streams of lava may be traced from their waters 
; ee ; diieon’ ahd 
*Dr. Daubeny is a promising mineralogist, and pupil of Jam rh = 
Bockland—he ss fost har from At ioe fmes thn: Evers AeTINg 
- 1 Re ee SO L f Scotiand an rewanc. 
Pew VIOUS: 
