a) Commission as Major in the Royal Regiment of Artillery, 1825.
b) Commission as Lt. Col., 1825.
c) Commission as Colonel, 1830.
d) Letter from the Duke of Wellington at Frente Guinaldo: orders the battering train to be halted at Villa de Ponte, 29 Aug 1811.
e) Letter from the Duke of Wellington at Frenti Guinaldo: approves his arrangements and asks his opinion on iron howitzers, 05 Sep 1811.
f) Letter from the Duke of Wellington at Frente Guinaldo: asks him to send forward 4 iron howitzers, 13 Sep 1811.
g) Letter from the Duke of Wellington at Frente Guinaldo: specifying the quantity of guns and ammunition to march from Almeida, 07 Jun 1812.
h) Copy of a letter from the Duke of Wellington to Lt. Col. Dickson regarding Sir John May's pension, 04 Feb 1814.
j) Letter from Frederick, Duke of York, informing him of the granting of the K.C.B., 24 Apr 1815.
k) Printed letter signed by the Duke of Wellington sending the decoration of the 2nd Class of the Order of St. Anne granted by the Emperor of Russia, 19 Aug 1815.
l) Letter from Sir Charles Broke at Cork: concerning the possibility of replacing brass with iron in the field and the progress made towards it, 28 Nov 1819.
m) Letter from the Earl of Munster sending the decoration of Knight Commander of the Royal Guelphic Order for services during the Peninsular War, 12 Aug 1822.
n) Letter from Lord Fitzroy Somerset notifying him of his nomination for a Lieutenant Colonelcy in the Horse Artillery, 01 Aug 1825.
o) Letter from the Duke of Wellington assuring Col. May he cannot interfere in military appointments, 03 Jul 1830.
p) Letter from Lord Maryborough: hopes he soon recovers his health, 29 Apr 1840.
q) Copy extract from 'The Times' on the occasion of Col. May's retirement detailing his past services, 18 Oct 1841.