Leave of absence having been thus granted by the College of Physicians and St. Bartholomew's Hospital, Harvey had only to get a substitute for his Court appointment. An undated letter written from abroad by Harvey to Mr. Secretary Dorchester, says: "Before I went I entreated and appointed Dr. Chambers and Dr. Bethune [physicians in ordinary to the King] and one Dr. Smith of London, one of them at all occasions to perform the duty for me; and I acquainted the household therewith [though] it is not usual [to do so] for serjeant [surgeon] Primrose was away above a year (and he is surgeon of the household) and yet none were put in his place to wait whilst he was in Germany with my Lord Marquis. Sir Theodore Mayerne [too] in Switzerland in King James his time was away very long and none put in his place." The letter was written upon an unfounded report which had reached Harvey in his absence that Dr. Adam Moesler "hath gotten to be appointed to wait in my place for the household."
Dr. Aveling's care has traced the course of the travellers on this journey. Sir Henry Mervyn writes to Nicholas (clerk of the Council) under the date of the 28th of July, 1630, "of having put over my Lord Duke [Lennox] for the coast of France." The journey was therefore begun at this date, but the Duke and his retinue seem to have stayed for a time in the towns upon the French coast, for on the 2nd of August Sir Henry Mervyn writes that he is going to attend the Duke of Lennox, and purposes to be in the Downs, &c.; and again on the 10th of August he says he has landed the Duke of Lennox at Dieppe. On the 23rd of September of the same year Edward Dacres writes to Secretary Dorchester that the Duke of Lennox is now settled in Paris for the winter; and again on the 22nd of November, saying that the Duke is willing to stay in Paris, and that "in the spring he intends the tour de France, and in the end of the summer to go into Italy, unless the continuance of the wars or the plague hinder him."
Dacres writes again, on the 5th of April, 1631, that the Duke is still in Paris but he thinks of going out of town for a few days. Harvey, however, was in London on the 8th of October and on the 22nd of December, 1630, so that he probably joined the Duke in Paris in the spring or early summer of 1631. Nothing is known of the movements of the party after April, until Dacres writes again to Dorchester in August, 1631, saying: "Blois proved a place not long to be endured by my Lord because of the plague which grew hot there, as Tours likewise, where we made little stay, so that we came down to Saumurs there to pass the dog days from whence we are now parting they being at an end. My Lord hath continually been in good health and intends now to follow your Lordship's directions this winter for Spain whither we are now bending our course (_viâ_ Bordeaux) where we shall be before the latter end of September."