Abrasion Resistance 
Tests indicate that angelique is superior to teak and white oak in resisting 
abrasion. Service trials on the landing decks of aircraft carriers show that 
angelique wears at least as well as teak under these rigorous conditions. 
Weathering Ability 
When exposed to weathering without a protective coating, angelique develops 
characteristic hairline checks that cover practically all of the surface. This 
checking does not appear to become more extensive with time and is not dis- 
qualifying for most structural uses. The heartwood is quite resistant to 
moisture absorption and in this respect is comparable to white oak. 
Fastening Strength 
The Material Laboratory, New York Naval Shipyard, found that angelique holds 
wood screws at withdrawal loads about one-third greater than those of teak 
and white oak. A similar relationship could be expected to apply for drift 
bolts, lag screws, and other types of fastenings, depending on frictional re- 
sistance. 
Silica Content 
The high degree of resistance of angelique to marine borer attack has been 
generally attributed to the relatively high silica content of the wood. This 
is one of the very few American legumes that accumulate silica, and in Dicorynia 
it occurs in the vertical parenchyma cells and in the marginal cells of the 
wood rays. The individual particles are generally about 0.001 inch in diameter. 
It has been reported that the rouge form lacks silica; however, every authentic 
specimen of all forms of angelique examined at the U. S. Forest Products Labora- 
tory was found to contain silica. Judging from the reports of a number of in- 
vestigators, the silica content is extremely variable and may account for the 
variation in machinability and borer resistance. Tests on individual specimens 
show a range of variation from 0.20 to 2.92 percent of the weight of the dry 
wood in the three forms of angelique. 
Silica determinations made on the three forms of angelique at the U. S. Forest 
Products Laboratory are given in table h. 
Availability 
Angelique is available in thicknesses from k/k to l6/h and in average widths 
of about 8 inches; infrequently, boards are cut to a width of 18 inches. Poles 
and piling are readily available in 40- to 60-foot lengths. Timbers may be 
Kept. No. 1787 _5_ 
