398 The American Geologist. June, i904. 
small collection or meteorites mainly from falls within tlie 
Louisiana Purchas': area accompanies this exhibit. 
Incidentally it may be remarked, that the Mexican Govern- 
ment has taken possession of the Ranchito mass and built 
around it a substantial stone house to protect it from the rav- 
ages of collectors. 
Exhibit of radio-active minerals. The United States 
Geological Survey has sent out a circular preparatory to the 
exhibit which, under the management of Mr. Geo. F. Kunz, 
the survey will make at the Loui$iana-Purchase Exposition 
during the coming summer at St. Louis, asking co-operation 
of all who are interested in radio-activity. The collection 
which will be on exhibition will be the most notable ever made. 
''It will include specimens of every known radio-active substance, 
whether obtained from minerals and ores, from mineral waters, or from 
petroleum wells. There will be shown also authentic specimens of 
radium compounds that have been made by noted investigators. Ev- 
erything relating to the source, manufacture, and application of radium 
will be exhibited, including all chemicals obtained from the separation 
of various radium compounds, and all instruments and devices with 
which it is proposed to apply radio-activity in medicine, science, and 
the arts. An interesting feature will be the portraits and the pub- 
lications of celebrated radimii discoverers and investigators, together 
with photographs of their laboratories and apparatus, and autograph 
letters from some of them." 
Field courses, in Geology. A joint announcement has 
been issued by Harvard University, University of Chicago, 
Columbia University, Johns Hopkins University and the 
Teachers' School of Science of the Boston Society of Natural 
History, setting forth the various courses ot field study that 
will be conducted by these institutions in the season of 1904. 
Four such courses will be given by the professors of Harvard ; 
four by the University of Chicago; one by Columbia Univer- 
sity; three by Johns Hopkins and two by the Boston Society 
of Natural History. ' Each of these courses will be under the 
guidance of a geologist familiar with the geology of the region 
studied. For the purpose of making the trips useful to all 
participants the parties are limited to ten or twelve. The re- 
gions to be examined range as far west as Hawaii and as far 
east as the Atlantic seaboard. 
Such study excursions are coming to be common. As 
the Geological Society of America has no meeting this (com- 
ing) summer, and as the American Association for the Ad- 
vancement of Science has its regular meeting in the winter, it 
may be expected that many will resort to these courses. The 
terms of admission and the costs of each may be learned by 
application to the various geological departments. Tn many 
cases the participants are required to prepare for publication 
a descriptive thesis on the geological phenomena seen and 
studied . 
