262 Scientific Intelligence. 
moves, it is difficult to trace the effect produced by the column 
smoke. One person, however, firing from an elevated position 
and at a distance of fifteen or twenty feet. sane the flasks down 
d 
ond College of Science for Ireland, Dublin, May 28, 1868. 
P.S.—Since bets J the foregoing, it occurred to me to fill the 
box with ammoniacal gas and to discharge rings from this ats 
column of the ast of hydrochloric acid. In this case the ring, | 
before reaching the column, is perfectly invisible, and the existens — 
a = column is only seen by slight traces of partially condensed 
As was expected, a beautiful ring appeared, from theca 
inition of ae two gases, when the ammonical ring re ached the 
col il, Mag., IV, xxxvi, 12, July, 1868. | 
June 16, 1868. 
Il. MINERALOGY AND GEOLOGY, 
Sty Twentieth Sp Report of the Regents o the te Cet 
s here reproduced his very importan memoir ‘6 Gra 
pablised by the Canadian Survey, with ‘vou additional 0 
=i connection with a statement of his se ahem et Tom at 
structure of some species of Spirifera, on p. 256, on 
ig : ie B. Meek who has "pei 
Ae 1866. Mr. Hall, in a letter written a Fi the 
to one "of the editors of this Journal, claimed that baa tet 
in 
. y: ki 4 
est allusion to Mr, Meek’s earlier publication. Mr. Meek 1” * ely 
article, May, 1867, alludes in a note to this fick ee 
urges ‘that his article in the Proceedings was not pa 
POE peated =< not yet — je one cee 
