( 221) 
REPORT OF THE DIRECTOR OF THE 
LABORATORIES. 
Dr. N. L. Brirron, DrrectTor-In-CHIeEF. 
Str: Ihave the honor to submit the following report for 
the year ending January 1, 1904. 
The appropriation for the laboratories has been expended 
chiefly in securing additional microscopes and lenses, in the 
increase of the equipment for research in chemical physiol- 
ogy and in the purchase of supplies of all kinds for the 
increasing number of investigators. The usefulness of 
the laboratories has also been greatly increased by the con- 
struction of suitable wall-cases and shelving, by the aid of 
which the apparatus may be properly cared for and kept in 
order. Chemical desks and tables for the use of individual 
workers have also been added. 
The collection illustrating the development and history of 
the microscope, donated by Mr. C. F. Cox, has been arranged 
for display by means of the additional necessary cases pro- 
vided for that purpose. 
Meteorological observations have been continued. The 
thermographic and precipitation records are filed in suitable 
volumes which contain the continuous series of observations 
begun in 1900. The total precipitation for the year amounts 
to 56.6 inches. The total number of days between the latest 
spring frost and the earliest freezing temperature of the 
autumn amounts to 170 days, in comparison with which it is 
interesting to note a similar period of 168 daysin 1902. The 
results of the first years’ observations with the Hallock soil 
thermograph have been discussed in a paper published in the 
Monthly Weather Review of the United States Weather 
Bureau for August, 1903, and reprinted as CONTRIBUTION 44 
in the Garden series. 
The results of my investigations upon the influence of light 
and darkness upon growth and development of plants, com- 
pleted in the previous year, are set forth in Vol. II of the 
