I CONCEIVE it necessary to make you acquainted with the following circumstance:--The department of Calais having elected me a member of the National Convention of France, I set off from London the 13th instant, in company with Mr. Frost, of Spring Garden, and Mr. Audibert, one of the municipal officers of Calais, who brought me the certificate of my being elected. We had not arrived more, I believe, than five minutes at the York Hotel, at Dover, when the train of circumstances began that I am going to relate. We had taken our baggage out of the carriage, and put it into a room, into which we went. Mr. Frost, having occasion to go out, was stopped in the passage by a gentleman, who told him he must return into the room, which he did, and the gentleman came in with him, and shut the door. I had remained in the room; Mr. Audibert was gone to inquire when the packet was to sail. The gentleman then said, that he was collector of the customs, and had an information against us, and must examine our baggage for prohibited articles. He produced his commission as Collector. Mr. Frost demanded to see the information, which the Collector refused to shew, and continued to refuse, on every demand that we made. The Collector then called in several other officers, and began first to search our pockets. He took from Mr. Audibert, who was then returned into the room, every thing he found in his pocket, and laid it on the table. He then searched Mr. Frost in the same manner, (who, among other things, had the keys of the trunks in his pocket,) and then did the same by me. Mr. Frost wanting to go out, mentioned it, and was going towards the door; on which the Collector placed himself against the door, and said, nobody should depart the room. After the keys had been taken from Mr. Frost, (for I had given him the keys of my trunks beforehand, for the purpose of his attending the baggage to the customs, if it should be necessary,) the Collector asked us to open the trunks, presenting us the keys for that purpose; this we declined to do, unless he would produce his information, which he again refused. The Collector then opened the trunks himself, and took out every paper and letter, sealed or unsealed. On our remonstrating with him on the bad policy, as well as the illegality, of Custom-House officers seizing papers and letters, which were things that did not come under their cognizance, he replied, that the _Proclamation_ gave him the authority.