[UPDATED: After receiving permission from the British Library I have been able to add urtext and modern editions of these duets.]
My research on mandolin-related prints prior to 1850 turned up a couple of previously unknown prints related to the mandolin from Great Britain in the 1750s. The first source is from the well-known printer John Walsh and is from 1757. This is the same year as the already known print by James Oswald. Besides the year of publication, there are a few more similarities: the somewhat strange spelling of “mandelin” for one. Otherwise it can also be commented that the repertory is late baroque instrumental music in both volumes.
Walsh, Forty Select Duets
This volume is preserved in the British Library with shelf mark Music Collections g.928.k. [UPDATE] I’m very grateful for the permission from the British Library for me to publish an urtext and modern edition (download see below). Dating is provided by the British Library as  which seems to suggest someone has found a secondary source confirming an exact date of print. I have however no knowledge of this secondary source, but the date does correspond with the one of the Oswald print.
The score has 18 pages (1 title page and 17 music pages) and the title page reads:
Duets, Ariettas & Minuets
MANDELINS or CITTARS
By the best Masters.
N.B. These Airs are also proper for
two German Flutes or French Horns.
London Printed for & Sold by Jn.° Walsh at the Harp & Hoboy in Catherine Street in ye Strand.
The 17 music pages contain scores of two parts. None of these goes below or above the range of the English guittar, the instrument for which this print seems primarily meant. Unlikely Oswald, the pieces seem to have been collected rather than originally created for the print. Four times a specific composer is mentioned (Händel): numbers 1 (Air), 2 (Minuet), 20 (Air) and 22 (Minuet). Most of the pieces are entitled “Air” (36x) or “Minuet” (5x), with one exception: number 36 is a “Pastoral” (1x). And yes, that makes a total of 42, not 40 as mentioned on the title page.
Air (36x): 1, 3, 4, 5, 6, 7, 8, 9, 10, 11, 14, 15, 16, 17, 19, 20, 21, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 37, 38, 39, 40, 41, 42
Minuet (5x): 2, 12, 13, 18, 22
Pastoral (1x): 36
As can be expected the keys which suit the English guittar are favoured:
C major (17x): 1, 2, 4, 9, 12, 14, 16, 21, 26, 29, 30, 33, 36, 39, 40, 41, 42
G major (13x): 3, 5, 6, 7, 10, 11, 20, 23, 25, 27, 31, 34, 35
F major (6x): 13, 22, 24, 32, 37, 38
D major (4x): 17, 18, 19, 28
d minor (1x): 8
a minor (1x): 15
In terms of metrums there is plenty of variety:
2/4 (13x): 6, 7, 8, 11, 16, 17, 19, 27, 29, 31, 37, 39, 41
3/4 (10x): 1, 2, 4, 9, 12, 13, 15, 25, 35, 40
3/8 (8x): 18, 21, 23, 30, 32, 34, 38, 42
6/8 (4x): 3, 14, 22, 26
C barré (3x): 5, 10, 24
C (3x): 20, 28, 33
6/4 (1x): 6/4
Articulations used are limited: appogiaturas, tr trill signs, the occasional fermata and staccattissimo signs. Slurs are very infrequent.
Most likely this volume was indeed intended for the English guittar, and the mandolin (mandelin) was an easy alternative. It might be argued that this might still or also mean the 5- or 6-course baroque Milanese mandolin. John Goodin already speculated this might be the case with Oswald’s print (J. Goodin, James Oswald and the Eighteen Divertimento’s for two Guitars or two Mandelins, Mandolin Journal, May 2003, and online at: http://www.mandotopia.com/articles/oswald1.htm). NB: Rob MacKillop has recorded the pieces by Oswald and has also took the effort to do additional research on these pieces (https://robmackillop.net/guitar/18th-century-wire-strung-guittar/).
However, there is some evidence to claim the possibility that this print and Oswald’s are contemporary to the first Neapolitan mandolins in Great Britain. (See for example the portraits from the 1750s pictured in Sparks, The mandolin in Britain, 1750-1800, Early Music Journal, vol. 46, iss. 1, 4 May 2018, p. 55–66.) So we’ll have to call this inconclusive, until further sources arrive who might explain what the “mandelin” was exactly.
In conclusion, the Walsh print is a fine addition to our limited sources of printed music related to the mandolin. It seems to me to have been collected and/or adapted from existing pieces rather than composed which likely is true for Oswald’s Eighteen Divertimentos. I will soon publish about another piece related to the mandolin and printed in Great Britain in the 1750s. Together with Oswald, these pieces give us fresh insights into the world of plucked strings in Great Britain in the 1750s and how this contrasts with the continental developments (on which I will comment in the next article).
With the kind permission of the British Library I’ve created an urtext and modern edition. The urtext edition remains true to the original, even to the point of having the same bars and notes per staff. However, because of the difference in paper size I couldn’t put the same amount of staves on a page. I also had to resort to using a landscape layout to keep the note size readable enough. I have corrected a few things (mainly some missing accidentals), which are listed on the critical notes, but usually also clearly marked in the score.
The modern edition has a normal modern layout and makes it slightly easier to read the music. The urtext edition is only a score and doesn’t take into account page turning. The modern edition has both a score (which does take into account page turns) and separate parts.
I’m convinced that some of the pieces in this volume deserve a place on the stage, whether played by English guittar, Neapolitan or Milanese mandolin, or any other instrument (cittern, flute or horn are also mentioned on the title page). As usual you can download the editions for free. (If you enjoy the music, you can chose to show your appreciation and contribute to my research via the donation button – but it’s not compulsory at all.)