248 FOREST TREES OF NORTH AMERICA. 



Peabody Academy of Science, Salem, Massachusetts. 



Arkansas Industrial University, Fayetteville. Arkansas. 



Imperial Botanic Gardens, St. Petersburg, Enssia. 



American Society of Civil Engineers, New York", New York. 



Portland Society of Natural History, Portland, Maine. 



New Jersey Agricultural College, New Brunswick, New Jersey. 



State Agricultural College, Burlington, Vermont. 



State Agricultural College, College Station, Maryland. 



Union College Engineering School, Scheuectady, New York. 



Cornell University, Ithaca, New York. 



Hampton Agricultural and Normal Institute, Hampton, Virginia. 



Pennsylvania State College, State College, Pennsylvania. 



Ohio State University, Columbus, Ohio. 



Agricultural College of Missouri, Columbia, Missouri. 



University of Wisconsin, Madison, Wisconsin. 



State Agricultural and Mechanical College, Auburn, Alabama. 



University of Minnesota, Minneapolis, Minnesota. 



North Carolina Agricultural College, Chapel Hill, North Carolina. 



West Virginia University, Morgantown, West Virginia. 



State Agricultural College, Orono, Maine. 



Georgia Agricultural College, Athens, Georgia. 



Massachusetts Agricultural College, Amherst, Massachusetts. 



Tennessee Agricultural College, Knoxville, Tennessee. 



New Hampshire College of Agriculture, Hanover, New Hampsh ire. 



Illinois Industrial University, Champaign, Illinois. 



State Agricultural College, Corvallis. Oregon. 



State Agricultural College, Manhattan, Kansas. 



Agricultural College of Mississippi, Starkville, Mississippi. 



Kentucky Agricultural College, Lexington, Kentucky. 



Claflin University, Orangeville, South Carolina. 



Purdue University, Lafayette, Indiana. 



Botanic Garden, Konigsberg, Germany. 



Engineer's office, Water-works, Boston, Massachusetts. 



Franklin Society, Providence, Rhode Island. 



Madison University, Hamilton, New York. 



Rochester University, Rochester, New York. 



Colby Academy, New London, New Hampshire. 



SPECIFIC GRAVITY 'AND ASH. 



The specific gravity and the ash of every tree of the United States have been determined (Table I) by Mr- 

 Sharpies, with the exception of the following : Clusia /lava, once detected upon the keys of southern Florida, but 

 not rediscovered; Gordonia pubescens, a rare and local species discovered in the last century upon the banks of the 

 Altamaha river of Georgia and never rediscovered; Pistacia Mexicana and Acacia Berlandieri, economically 

 unimportant species of the valley of the lower Rio Grande ; Cratccgus berberi/olla, a little known species of the 

 Red River valley; Cupressus Macnabiana, a rare and local species of California of little economic importance; and 

 Larlx Lyallii, a rare and local species of the northern Rocky mountains. 



At least two determinations of specific gravity have been made for each species studied, and, in the case of 

 woods of commercial importance, specimens were taken from many trees growing in widely different parts of the 

 country, and under different conditions of soil and climate. 



The specimens used for specific gravity determinations were made 100 millimeters long and about 35 millimeters 

 square, and were dried at 100 centigrade until they ceased to lose weight. The specific gravity was then obtained 

 by measurement with micrometer calipers and calculation from the weights of the blocks. 



Two determinations of ash were made from each specimen studied by burning small, dried blocks in a muffle 

 furnace at a low temperature. 



An average of the specific gravity and of the ash of all the specimens taken from the same tree was made, and 

 the average of these averages is given as the final result for the species ; equal weight is thus given to each tree itt 

 the calculations without regard to the number of specimens representing it. 



