These letters from John Manners, 3rd Duke of Rutland are largely written to William Cavendish, 3rd Duke of Devonshire, but include a letter each to his grandmother Rachel, Lady Russell, his aunt Rachel Cavendish, Duchess of Devonshire and Mr Hewett.
The letter to his grandmother concerns his wife who he explains is pregnant and suffering keenly with it which has preoccupied his time and left him forgetting to do other things. He writes about his worry of losing her and hoping it will not happen after he already lost his mother (Lady Russell's daughter Katherine) so young. He adds how happy he is with his choice of wife and that he is happy to remain living with Lord Lexington. He sends wishes to the Duke and Duchess of Devonshire and Mr Charlton.
The letter to his aunt Lady Devonshire concerns the will of his sister Rachel, which is to go before the Chancery. He wishes her to consider that the money if left to him would be invaluable but broken up amongst many will be of no help to anyone. He mentions that Lord Lexington and his second son have both been in a dangerous condition and are not yet fully recovered.
The letters John Manners sends to his cousin William Cavendish, 3rd Duke of Devonshire are largely concerned with the legal dispute between the partners of Portaway mine and the Duke of Devonshire about smithum, which the Duke believed was being created by deliberately breaking down larger lumps of ore to avoid taxes.
In detail the topics of the letters include: the election and the Duke of Devonshire's success at Derby; a matter concerning Sir Curzon, Lord Hartington and Mr Barker; the Nottingham and Newark, and Mansfield elections; the news from France about which route will be taken, it not being by Maestrich; insurrection in Scotland and Dutch regiments landing; battle tactics of leaving fortresses or heading into mountains; the threat of assistance from foreign troops and protecting the south; the cost of calling up militia for each county; news of a [chair] falling on the Grand Duke; an issue with dishonesty in Lord Devonshire's mine and making an example of the offender; Manners' reference to the late Mr Sherrard mentioning fraud that occurred in the mines when the oar was broken into [crithage?]; Manners' request to let him know what he wishes to happen and he will arrange it so it does not appear to come from the Duke; his forgetting who looks after his affairs in these mines; Lord Granby's wish that the Duke would take a trust in his marriage settlement; Manners' picture room which takes up much of his time and for which the stonework is nearly finished with the roof coming next; the Duke's love of being abroad; Manners' wishes for his and the Duchess's good health; a dispute between the partners and the Duke concerning Portaway mine; Manners being told that the Duke directed the agents to take the duty on the smithum as well as the round [ground] ore; Mr Tissington's explanation of the difficulty of separating smithum from calk and the miners rather wishing to bring up round ore than smithum; the method of proceeding with the mine issue either by bill for fraudulent practices or to try establishing the right to tythe smithum; Manners' barmaster Findley bringing a copy of the agreement between the Duke and the partners of Portaway; Manners' request for his steward Parker and the solicitor at Bakewell to look through the agreement before he signed because he felt it tied himself and the Duke down whilst leaving the partners at liberty; business in London and choosing to delay repayment of a debt so as to be receivable to the cause; assistance from Captain John Vernon to do with a copy of a quo warranto inquisition/'inspeximus' record which could be brought to the court of the Chancery; the connection between Manners' barmaster and the partners at Portaway and his suggestion to the Duke of dismissing the barmaster and replacing him with another because in a trial it is clear he would support the partners, and his dismissal may weaken any testimony despite increasing his animosity; requesting the Duke's opinion on the dismissal of Manners' barmaster; a copy of the bill preferred against the Portaway partners and Manners' opinion of it concerning smithum being the work of customary machines and how the partners' plea of making it merchantable will stand in a Court of Equity; Lord Granby's intention to purchase Manners' house in town; mention of the Weekly Club; Lord Burlington's situation..."freed from the dismal condition in which he lies"; Lord Bedford blessed as a non-conformist; a request to the Duke to find another method of filling up the "Clubb" at Whites before it is filled up by those meeting at Newmarket; Mr Barker's potential replacement who has been recommended by Mr Wright as a kinsman of his; Manners' approval in principle of appointing Mr Wright's suggestion but needing to check whether Barker kept the mineral and court records and whether the mineral court required someone with more business experience that comes with age; his consideration of Mr Froggatt for the mineral court and requesting the Duke's opinion on the matter.
The final letter in this series is to Mr Hewett, in which Manners apologises for not having written sooner owing to the fact he has little news from England. He writes that his sons Lord Granby and George are happily married and both have sons. He writes that he remains in London over summer to oversee the progress of a "diminutive palace" he is erecting in a field overlooking the park between Knightsbridge and Kensington. He mentions that his daughter has married Mr Theraton of Nottinghamshire and has had a son. He mentions that Mrs Drake and Lord William and family are well. He asks Hewett to "burn the bond" and also informs him that the Duchess of Rutland is dead. He provides further news of people who have died, parsons who have swapped parishes and Lords granted the Order of the Garter. He mentions his picture room at Belvoir is finished and that he does his own painting too.