RCA only licensed these recordings for release. They had nothing to do with Boulton's original field recording expedition in 1934, which was largely financed by the philanthropist Sarah Lavanburg Straus, as in the "Straus West African Expedition" referenced on the cover of the album.
There are numerous references to Boulton using Presto equipment in her 1930s and 1940s fieldwork, though I haven't seen one that describes the 1934 expedition in particular that mentions Presto. She might cover it in her autobiography "The Music Hunter." Also, about ten years ago, Indiana University released a CD-ROM devoted to the 1934 fieldwork: "Music and Culture of West Africa: The Straus Expedition." Straus was the philanthropist Sarah Lavanburg Straus. There's more information here: http://www.indiana.edu/~rcapub/v21n3/p08.html. It seems like a pretty comprehensive package, and may include information or better photos of Boulton's recording gear.
Library of Congress
From: Association for Recorded Sound Discussion List [mailto:[log in to unmask]] On Behalf Of Roger Kulp
Sent: Wednesday, August 21, 2013 11:35 PM
To: [log in to unmask]
Subject: Re: [ARSCLIST] Laura Boulton
RCA record equals RCA equipment. Roger > Date: Wed, 21 Aug 2013 00:28:42 -0400> From: [log in to unmask]> Subject: Re: [ARSCLIST] Laura Boulton> To: [log in to unmask]> > Thanks for all of your hard work, Dr. B, in checking out that photo> and all of those fine leads to Laura Boulton images! I have known the> image of her from this album 40 years, but never thought to look for> another one with recording equipment. On the 1934 expedition that> produced this set alone she cut 464 discs. So I guess it wouldn't be> unusual for her to be seen with recording equipment!> > David N. Lewis> Cincinnati, OH