Personal and Scientific News. 259 
6. Optically positive character of the uniaxial figure, 
in distinction from talc, serpentine, etc. 
7. Occasional twinning, observed in crystals enclosed 
in limestone. 
8. Certain chemical tests, in confirmation of the op- 
tical diagnosis. 
A Joint Announcement of Field Course.s in Geology; 
Summer of 1^05, has lately been issued, containing a list 
of field courses in geology offered for the summer of 1905 
by several imiversities in dififerent parts of the United 
States. 
The colleges and universities named in the list below 
have agreed, under certain conditions, to give credit for 
summer field work in geology in such courses as are de- 
scribed in the joint announcement. Students in any of 
these institutions wdio wish to take advantage of this ar- 
rangement must previously consult the Dean of the de- 
partment in which they are registered, as to the course that 
they wish to take and as to the requirements for gaining 
credit for work done in it. 
Amherst College. University of Missouri. 
Beloit College. University of North Carolina. 
University of Chicago. Northwestern University. 
Colgate University, Oberlin College. 
Columbia University. Ohio Wesleyan University. 
Hamilton College. University of Rochester 
Harvard University. Syracuse University. 
Johns Hopkins University. University of Toronto. 
University of Kansas. Vanderbilt University 
Massachusetts Institute of Wesleyan University. 
Technology. Western Reserve University. 
McGill University. Williams College. 
University of Michigan. University of Wisconsin, 
University of Minnesota. Yale University. 
' r 
The ntimber of courses olYered and the professors from 
whom the joint announcement and information about 
.special courses may be obtained are as follows : 
Intercollegiate Appalachian Course — -Prof W. B. Clark. 
University of Chicago, (Five Courses)— Prof. R. D. Salisbury. 
Columbia University, (One Course) — Prof. A. W. Grabau. 
Harvard University, (Three Courses) — Prof. .1. B. Woodworth. 
Johns Hopkins University, (One Course) — Prof. W. B Clark. 
University of Kansas, (One Course) — Prof. E. Haworth. 
University of Minnesota, (Two Courses) — Prof. C. W. Hall. 
University of North Carolina, (One Course) — Prof. C. Cobb. 
Ohio State University, (One Course) — Prof. C. S Prosser. 
Leland Stanford Junior University, (Two Courses) — Prof. J. C. 
Branner. 
University of Wisconsin, (One Course)— Prof. W. H. Hobbs. 
The 'courses announced for relative1,v distant fields 
are : Glacial Geology in the Rocky Mountains by Prof. 
Salisbury of Chicago; General Geology in ^fontana, by 
