to determine its working propertiesy If we are able to kiln 
dry and work it satisfsc'orily indict.tion-1 are that it will 
be a fairly satisfactory substitute for spruce in spruce sizes 
in wing beams, struts, etc. This matter is receiving the stten- 
tion of the laboratory. 
Balsam Fir.--Balsam fir is somewhat lighter than 
spruce  ad considerably lower in all its strength properties, 
and does not give promise of being satisfactory in airplane 
construction. 
Fir, Gr-nd,_roble)snd White.-rard fir as tested 
was slightly heavier than spruce while the Noble and vhite 
fir were slightly lighter. The strength properties of these 
species c npare very favorably with spruce except the shock 
resisting ability of the white fir which is a little low. 
This, however, may be accidental. The remarks given above 
for Amabilis fir will apply to these species. 
Black Herilock.--This species is quite a little heav- 
ier than spruce and lacking in stiffness. 
Eastern Hemlock.--Strength properties along consider- 
ed eastern hemlock would appear to be a substitute for spruce, 
but the lumber runs shaky, is liable to. heart-rot, has numer- 
ous knots, and develops shakes and checks in service. It need 
not, therefore, be considered. 
Western emlock.--Western hemlock is heavier than 
spruce but not quite so heavy as Douglas fir. It is low in 
its shock resisting ability, but strength alone considered