They were found also guilty of a wilful concealment of such facts, as they knew, if communicated, would have invalidated their own testimony.  I was instrumental in detecting them on one of these occasions myself.  When Mr. Dalzell was examined, he was not wholly unknown to me; my Liverpool muster-rolls told me that he had lost fifteen seamen out of forty in his last voyage.  This was a sufficient ground to go upon; for generally, where the mortality of the seamen has been great, it may be laid down that the mortality of the slaves has been considerable also.  I waited patiently till his evidence was nearly closed, but he had then made no unfavourable statements to the house.  I desired, therefore, that a question might be put to him, and in such a manner, that he might know that they, who put it, had got a clue to his secrets.  He became immediately embarrassed; his voice faltered; he confessed with trembling that he had lost a third of his sailors in his last voyage.  Pressed hard immediately by other questions, he then acknowledged that he had lost one hundred and twenty, or a third of his slaves, also.  But would he say that these were all he had lost in that voyage?  No; twelve others had perished by an accident, for they were drowned.  But were no others lost beside the one hundred and twenty and the twelve?  None, he said, upon the voyage, but between twenty and thirty before he left the Coast.  Thus this champion of the merchants, this advocate for the health and happiness of slaves in the middle passage, lost nearly a hundred and sixty of the unhappy persons committed to his superior care, in a single voyage!

The evidence, on which I have now commented, having been delivered, the counsel summed up on the 17th of June, when the committee proceeded to fill up the blanks in the bill.  Mr. Pitt moved that the operation of it be retrospective, and that it commence from the 10th instant.  This was violently opposed by Lord Penrhyn, Mr. Gascoyne, and Mr. Brickdale, but was at length acceded to.

Sir William Dolben then proposed to apportion five men to every three tons in every ship under one hundred and fifty tons burden, which had the space of five feet between the decks, and three men to two tons in every vessel beyond one hundred and fifty tons burden, which had equal accommodation in point of height between the decks.  This occasioned a very warm dispute, which was not settled for some time, and which gave rise to some beautiful and interesting speeches on the subject.

Mr. William Smith pointed out in the clearest manner many of the contradictions, which I have just stated in commenting upon the evidence; indeed he had been a principal means of detecting them.  He proved how little worthy of belief the witnesses had shown themselves, and how necessary they had made the present bill by their own confession.  The worthy baronet, indeed, had been too indulgent to the merchants, in the proportion he had fixed of the number of persons to be carried to the tonnage of their vessels.  He then took a feeling view of what would be the wretched state of the poor Africans on board, even if the bill passed as it now stood; and conjured the house, if they would not allow them more room, at least not to infringe upon that which had been proposed.