18 UTILIZATION OF GALIFORNIA RUCALYPTS. 
Of the five species of eucalyptus tested, the highest strength values 
are possessed by sugargum. It appears from a general résumé of the 
mechanical tests on the five species of eucalyptus that there may be a 
considerable variation in the strength of the same species grown in 
different localities or of different trees cut in the same locality. The 
strength of some species, such as sugar gum, blue gum, and red gum, 
compares favorably with that of white oak, pignut, and shagbark 
hickory, while the other species rank with what are considered the 
weaker varieties of hickory. The number of tests made on the 
eucalypts are too few to warrant final conclusions, but they indicate 
strongly that at least several species are equal to the better grades 
of hickory in bending and crushing strength. 
Of course the quality that makes hickory superior to other woods 
for certain uses, particularly for vehicle construction and handles, 
is its toughness. Even though eucalyptus equaled or exceeded 
hickory in strength and stiffness, it could not compete with hickory 
for these uses unless it combined with its strength and stiffness a 
degree of toughness approaching that of the hickory. The experi- 
ments on eucalyptus have not yet been carried far enough to afford 
data for a comparison of its toughness with that of hickory. 
Table 4¢ gives the partial results of tests on Australian eucalypts. 
In the case of blue gum the results are slightly higher than those on 
California-grown material, while red gum grown in Australia shows 
a lower strength than the average of the two California shipments. 
Of the other species in Table 4, yate, wandoo, and ironbark average 
about the same as California sugar gum, and the others about the 
same as California blue gum. 
a Taken from the Supplement to the Western Australia Timber Tests. No state- 
ment was included as to whether the oven-dry weights were computed with the aid 
of a shrinkage factor. It is possible, therefore, that these tests were not made by 
exactly the same method as that followed in the case of the California woods. 
[Cir. 179] 
