For two years the appointment remained vacant, but in 1714 it was again conferred upon
John, now Duke of Marlborough, who held it until his death, in 1722. He was succeeded, as follows, by
William, Earl of Cadogan, on 22nd June, 1722, and by
John, Duke of Argyle and Greenwich, on 3rd June 1725.
At this period there is an unaccountable confusion among the various authorities. The 'British Chronologist' and the 'Biographia Britannica' make the list run as follows:—The Duke of Argyle and Greenwich was succeeded, in 1740, by John, Duke of Montague, and resumed office again, for three weeks, in 1742, when, for the last time, he resigned all his appointments, being again succeeded by the same Duke of Montague, who continued to hold the office until 1749, when he died.
'Grose's List,' on the other hand, makes the Duke of Argyle's tenure of office expire in 1730, instead of 1740, and makes no allusion to his brief resumption of the appointment in 1742, and 'Kane's List' has followed this. It is possible that for the brief period that he was in office the second time, no letters patent were issued for his appointment, which would account for its omission in most lists; but the difference of ten years in the duration of the first appointment is more difficult to account for. There is no doubt that, in 1740, the Duke of Argyle resigned all his appointments for the first time, but it is not stated whether the Master-Generalship was one, although it has been assumed. On the other hand, he might have been away during these ten years to a great extent, or allowed his officers of the Ordnance to sign warrants, thus giving an impression to the casual student that he no longer held office. The manuscript in the Royal Artillery Library, already referred to, bears marks of such careful research, that one is disposed to adopt its reading of the difficulty, which is different from that taken by Grose's and Kane's Lists, and agrees with the other works mentioned above.
After the death of the Duke of Montague, the office remained vacant until the end of 1755, when it was conferred upon
Charles, Duke of Marlborough, who held it until his death, on 20th October, 1758.
During the vacancy immediately preceding the appointment of the last-named Master-General, Sir J. Ligonier had been appointed Lieutenant-General of the Ordnance, and for four years had performed the duties of both appointments,—acted as Colonel of the Royal Artillery, and Captain of the Cadet Company. A few months after the death of the Duke of Marlborough—namely, on the 3rd July, 1759—he was appointed Master-General, being by this time
Field-Marshal Viscount Ligonier. He was succeeded, on the 14th May, 1763, by