10 REPORT OF THE SECRETARY. 



other scientific institutions and individuals. During the past year the 

 compilers have completed the tables of rain for 600 Smithsonian stations 

 for the years 1S68, 1869, and 1870, and of 220 military posts from Decem- 

 ber, 1861, to November, 1871. The result of all the observations has 

 been incorporated in the charts published in 1872, but the tables will be 

 combined with those already published at some future time. 



It is proper here to express our obligations for the valuable co-opera- 

 tion of the Medical Department of the Army, under Surgeon-General 

 Barnes, who has given us free access to all the unpublished records ; and 

 also for that of the Department of Agriculture, under its former commis- 

 sioner, General Capron. These tables furnish the means for important 

 deductions intimately connected with the agriculture, commerce, and 

 mechanical industry of the country, while they constitute a valuable con- 

 tribution to the physical geography of the globe. 



This memoir is one of a series embodying the results of all the labors 

 of the Smithsonian Institution in regard to the meteorology of the United 

 States. These will include not only all the observations which have been 

 made under its own direction, but also the discussion of all that has been 

 made by other parties. The whole series will embrace the tabulation 

 and discussion of observations on the temperature, atmospheric pressure, 

 direction and force of the wind, moisture of the air, and miscellaneous 

 phenomena. 



Another work, that of Dr. Horatio C. Wood, jr., of Philadelphia, on 

 the fresli-icater algce, was briefly noticed in the report for 1870. It forms 

 a complement to the great work on the marine algse by Dr. Harvey, 

 published in 1858 by the Smithsonian Institution. It is illustrated by 

 numerous drawings, made principally under the microscope, and will 

 serve to illustrate an obscure department of botany, and also to furnish 

 the means by which investigators of minute microscopical organisms may 

 compare recent and fossil forms. The work was presented to the Amer- 

 ican Philosophical Society and also to the Academy of Natural Sciences 

 of Philadelphia, but the expense of the engravings prevented either of 

 these societies from undertaking its publication, although it was consid- 

 ered entirely worthy of their adoption. It was referred by the Institu- 

 tion to Dr. Torrey and Professor Barnard for critical examination, and 

 published on their recommendation. 



A large part of the material for this work was gathered by Dr. 

 Wood himself, although he was indebted to several persons for aid, 

 especially to Dr. J. S. Billings, of the United States Army, for col- 

 lections made near Washington ; to Professor Kavenel, of South Car- 

 olina, for collections in Texas, South Carolina, and Georgia; to Mr. 

 C. J. Austin for specimens gathered in Northern New Jersey ; to Mr. 

 William Oanby for collections obtained in Florida; to Professor Sereuo 

 Watson for others from the Pocky Mountains; and to Dr. Lewis for 

 specimens'from the White Mountains. The work embraces all families 



