August 3, 1950 
Mr, Paul Eng strum, 
. ( ,A’ 803 Dupont Circle Building, 
® 1346 Connecticut Avenue, N. W. 
, Washington 6, D. C. 
Dear Mr. Eng strum; 
May I recall to your attention your kindness in assigning 
' to me one hand operated ^ir-O-Spra ) Mo. 88 for experimental 
testing, for which I made acknowledgment under date of November 
8, 1949» 
I beg to advise that I used this hand spray during field 
work in a remote section of the eastern part of the Republic of 
Panama during February and March last, and that I found it highly 
successful. 
I was engaged in the collection of specimens of birds 
for the TJ. S. National Museum and much of the time lived in shelters 
similar to those shown in the accompanying photograph. Our speci¬ 
mens were kept in trays in fiber containers and were set out 
regularly each day to get the air, in order that they might dry 
properly for shipment. Occasionally we were quartered in native 
houses where similar prirrttive conditions prevailed. 
Our main concerns in this work are guarding specimens 
against ants which are highly destructive, and resistance against 
flies, including mosquitoes. 
I beg to report that the Air-O-Spra proved highly effective 
and that with judicious use of it we experienced no trouble. 
The instrument is compact, carries well in that the fluid 
does not leak as in the ordinary type spray pumps, and I look for¬ 
ward to use of this particular instrument on future expeditions. 
