A certified log of each endurance swim was completed and signed by designated officials. In order to facilitate her next scheduled endurance swim, Mercedes made arrangements for the official log of the swim she had just completed to be sent to the superintendent of the baths where her next event was to be held, for their guidance, but with instructions to keep it safe for her collection.

Unfortunately only one of these logs is available for reproduction. But they do still exist. Nineteen certified endurance swim logs together with charted maps of some of her open water swims, handwritten on heavy cartridge paper, were found in the attic of a house in South London by a tenant. In 1999 (many years after they were found) they were given to Sotheby’s to sell after the finder had tried unsuccessfully to trace possible descendants of Mercedes. This sale went ahead without the knowledge of Mercedes’s family – who would of course have either halted it until ownership was proved or, alternatively, bid for the items themselves. This opportunity was denied them, and it was felt that to try to retrieve them from the purchasers would involve unaffordable legal fees, as the documents were already out of the country before the sale was brought to their attention. 

Photocopies of just three of the documents were eventually obtained from the buyers. One of these was the log covering the Dublin endurance swim on the 9-10 February 1930 (reproduced on this website under ‘Endurance Swims, Dublin, 28 hours).  

A two-page list of the documents was compiled by the seller before handing them over to Sotheby’s. A copy of this list was eventually obtained from him, and is reproduced below. Although most of the documents listed are ‘sight-unseen’, there is ample written evidence in Mercedes’s archives verifying the completion of all 27 swims – letters written by local authorities who organised and validated the swims, posters, newspaper articles, and photographs taken before, during and at the finish of each event. Reference to the 19 swimming logs listed in the Sotheby’s sale (as well as the 8 unlisted ones) appear in letters in the archives from Mercedes to local authority officials, giving clear instructions to forward the logs either to herself direct, or care of the superintendent of the next corporation baths where she was to perform an endurance swim. She would then eventually collect them from the superintendent. During her travels she endeavoured to keep track of where each log was, and chased up missing ones. For example, in the summer of 1930 she wrote to Charles N. Bond, Superintendent of Wolverhampton Corporation Baths Department, enquiring about the whereabouts of three of them, and he wrote back to her on 2 August saying:

It is obvious that, because of her nomadic lifestyle, the bundle of swimming logs and charts found in the house in South London either got left behind accidentally when she was moving from one temporary address to another, or possibly she asked someone to look after them and they were never returned to her. These logs belonged to Mercedes and should be in her archives. They constitute a record of her swimming achievements, and because of her experience with Dr Dorothy Logan’s hoax, she would never knowingly have parted with them.