Pitt's second ministry had begun in May 1804 under inauspicious circumstances. Britain was at war again with the Emperor Napoleon, and the pressure placed upon Pitt would have been astronomical. A sad glimpse of Pitt's mental state at the time was conveyed in a letter from Lavinia, the Countess Spencer, to her husband (and First Lord of the Admiralty) George, 2nd Earl Spencer. Writing on 31 August 1804, Lavinia told her spouse of Pitt's depressed demeanour after an unnamed 'man of business' saw him walking alone on the Mall (and St. James's Park):
“...a sensible well judging man of business (Imagine in the ordnance) who is much accustomed to transact affairs with Mr. Pitt [told a servant of Lavinia, Countess Spencer] of an interview which he had yesterday with this upright statesman [Pitt] - this Friend of Kross’s told him that he had for many years been in the habit of being tête a tête with him [Pitt] on business, & that he had seen him under circumstances which woud have appal’d the stoutest heart, & Calm, Collected & unoccupied did he always find him - but that Yesterday, what produced such an effect he coud not take upon him to say, He never saw a Man so utterly absorbed in profound thought, & so compleatly under the influence of anxiety & dejection - so that by no means coud he, the Man of business, make him Mr. Pitt attend one moment to that subject under which brought them together - this, Kross said, so struck his friend, that he himself had caught the same impression & he coud not but believe that what he had heard from various quarters was but too true namely that the K.[ing] is downright ill. - A very pretty kettle of fish! Oh goodness! - Harrison, of himself, asked me what was the matter with Mr. Pitt for that he believed him to be a diing [sic] man from his appearance - he Harrison was walking in the park Yesterday Morning very early, & he saw before him a Man walking by himself with his arms across, & apparently so taken up in thought & walking so uncommonly slow & unequally that it gave him a curiosity to see who it coud be, & on overtaking him he saw it was Mr. Pitt looking like death with his eyes staring out of his head & steadfastly fixed on the ground before him - Harrison says he coud hardly help starting at the oddity of the whole thing - for he believes Mr. Pitt never was seen walking up & down the Mall by himself Solus cum Solus (that’s good latin I am sure) before." 
Although the Countess attributed Pitt's mood to the King's failing health, it is difficult to determine the nature of his affliction. More on the potential causes of Pitt's poor health in 1804 will be discussed in a future post.
1. Lavinia, Countess Spencer to her husband George, 2nd Earl Spencer. Friday 31 August 1804. British Library, Althorp MSS 75931.