LEITNERIA FLORIDANA. 15 
as given in the census tables. Ochroma lagopus, one of a 
number of so-called cork woods enumerated by Wiesner,* 
is said to have a density of 0.250,f but I cannot place my 
hand on any determinations lower than this. Professor 
Nipher tells me that the specific gravity of common cork 
(the bark of Quercus Suber) is given by Ganot as 0.240. 
Although individual variability and the difficulties of deter- 
mining the specific gravity of porous and absorbent bodies 
like wood make it unwise to accept any of these figures as 
invariable, it appears from them that the wood of Leitneria 
is very markedly lighter than the bark of the cork oak, 
which itself is considerably lighter than any other wood of 
which a record can be found. 
0.16-0.20 
0.46-0.58 
0.61-0.65 
0.71-0.75 
0.91-0.95 
1,.26-1.30 
q y 
FREQUENCY OF TIMBER DENSITIES. 
The appended curve, compiled from the census tables, 
shows the relative frequency of occurrence of the different 
degrees of density in our native timbers, each co-ordinate 
representing a difference of .050, and each species falling 
within this range being represented by a vertical distance of 
* Rohstoffe, 578. 
+ Goodale, Physiological Botany, 145. 
11 
