2710 EDITORIAL 
but it may be conjectured that when the history of the stellar 
system shall become as serious and substantial a subject of study 
as the history of the earth now is, astronomers will find at least 
as great need for long lapses of time and for the secular endur- 
ance of thermal states as do the geologists and biologists. 
Meanwhile all solar inquiries are subjects of acute interest in 
common and the achievements of May 28 are matters of heartiest 
congratulation. M,C. CG, 
Tue George Huntington Williams Memorial Lectures, inaug- 
urated in 1897 by Sir Archibald Geike, have been continued this 
year by Professor W. C. Brogger, of the University of Chris- 
tiania, who delivered at the Johns Hopkins University two lectures 
on The Principles of a Genetic Classification of the Igneous 
Rocks, and five lectures on The Late Geological History of 
Scandinavia, as shown by changes of level and climate in 
southern Norway since the close of the glacial epoch. His 
long and thorough investigation of the igneous rocks of the 
Christiania region, so varied in character, well preserved and 
finely exposed, has qualified him to speak with authority upon 
the subject of their genetic relations, and renders his judgment 
upon the general problem of the classification of igneous rocks 
of the firstimportance. Until the text of these lectures has been 
published, it will not be in place to discuss the conclusions 
enunciated by Professor Brégger. The lectures on The Late 
Geological History of Scandinavia were based upon recent field 
studies of the glacial phenomena of that region. In addition to 
their special scientific value, they illustrate the remarkable ver- 
satility and energy of Professor Brogger, whose substantial con- 
tributions to the paleontology and stratigraphy, the mineralogy 
and petrology of the Christiania region have already awakened 
the admiration of his fellow workers. 
Professor Brogger also delivered his lectures on the Genetic 
Classification of Igneous Rocks at the University of Chicago to 
an appreciative audience of students and geologists, who assem- 
bled from various parts of Illinois and from Michigan, Wis- 
consin, and Minnesota. Je Pane 
