(26) 
January 20. Dr. Arthur Hollick, ‘‘ Palaeobotanical Ex- 
plorations in Alaska.” 
February 3. Professor H. M. Richards and Dr. D. T. 
MacDougal, ‘‘ Influence of Carbon Monoxide on Plants.” 
February 17. Dr. M. A. Howe, ‘A Collection of Algae 
from the Bahamas.” 
February 17. Dr. P. A. Rydberg, ‘‘Some Features of 
Plant Distribution in the Rocky Mountains.” 
March 2. Miss Ada Watterson, ‘‘ The Effect of Chem- 
ical Irritation on the Respiration of Fungi.” 
March 16. Dr. D. T. MacDougal, ‘‘ Explorations in the 
Delta of the Rio Colorado and in Baja California.” 
April 6. Professor H. M. Richards, ‘‘The Responses of 
Protoplasm, with especial reference to the lower plants.” 
April 20. Dr. N. L. Britton, ‘‘ Explorations in Florida, 
and Distribution of the Antillean Flora.” 
October 19. Dr. D. T. MacDougal, ‘‘The Mutants of 
the Evening Primroses.” 
November 2. Dr. Arthur Hollick, ‘¢ Discoveries of Fossil 
Plants on Long Island.” 
November 16. Mr. Ira D. Cardiff, «* The Development 
of the Sporangium in Botrychium.” 
November 16. Dr. N. L. Britton, ‘‘ Professor Engler’s 
Views of the Origin and Distribution of Plants in Northern 
Africa.” 
Meteorological Observations 
Meteorological observations have been continued through- 
out the year and the records have been added to the series 
which has been kept continuously since 1900. The total 
precipitation for 1904 amounts to 47.01 inches. The total 
period between the latest occurrence of freezing temperature 
in the spring and the earliest in the autumn was 167 days, 
compared with 168 days in 1902 and 170 days in 1903. In 
addition to the ordinary standard instruments a thermograph 
which records the soil at a depth of 12 inches, and the air, 
has been added to the equipment. <A second soil-thermo- 
graph is also in use by which the investigations begun in 1902 
