Here's a detail from the photo lightened-up in Photoshop.
David Billings follows our discussions and sends me his input via email. Today he wrote:
"The Daily Express was at times fitted with Wing Leading Edge De-Icer boots both when used by Captain's Merril and Lambie over the Atlantic and also by Sir Hubert Wilkins in the Arctic where it operated on skis.
I have no idea of what the boots were in the way of operation....i.e: whether pneumatically inflated or whether they seeped fluid but either operation would require a tank for compressed air or a tank for de-icing fluid.
References to the aircraft are in Merril's book, 'Wings of Man" and "The Last Explorer" by Simon Nasht"
To which I replied,
"I don’t see boots on the wings or props in this photo of the Daily Express or in film of Merrill’s departure (
https://youtu.be/ZUF622vTyk8) but it would make sense to add de-icing equipment for work in the arctic. Pneumatic boots are inflated by an engine-driven compressor, not a tank of compressed air. The tank could be alcohol for windshield and prop anti-icing but that would be one helluva lot of alcohol. We had an alcohol system on the DC-3 I flew, but the tank held only a couple gallons (and the line to the windshield ran overhead in the cockpit and leaked).
Whatever the tank is, it’s something Earhart didn’t have, and the photo was taken after the arctic work, so anti-icing seems like a good possibility.
BTW, I have a copy of “Wings of Man” ghostwritten by Jack L. King. Lots or errors. I was not aware of “The Last Explorer.” I just ordered a copy."