Had anything happened while Rachel and I were finishing the painted door? or, later, when I rode over to Frizinghall? or afterwards, when I went back with Godfrey Ablewhite and his sisters? or, later again, when I put the Moonstone into Rachel’s hands? or, later still, when the company came, and we all assembled round the dinner-table?  My memory disposed of that string of questions readily enough, until I came to the last.  Looking back at the social event of the birthday dinner, I found myself brought to a standstill at the outset of the inquiry.  I was not even capable of accurately remembering the number of the guests who had sat at the same table with me.

To feel myself completely at fault here, and to conclude, thereupon, that the incidents of the dinner might especially repay the trouble of investigating them, formed parts of the same mental process, in my case.  I believe other people, in a similar situation, would have reasoned as I did.  When the pursuit of our own interests causes us to become objects of inquiry to ourselves, we are naturally suspicious of what we don’t know.  Once in possession of the names of the persons who had been present at the dinner, I resolved—­as a means of enriching the deficient resources of my own memory—­to appeal to the memory of the rest of the guests; to write down all that they could recollect of the social events of the birthday; and to test the result, thus obtained, by the light of what had happened afterwards, when the company had left the house.

This last and newest of my many contemplated experiments in the art of inquiry—­which Betteredge would probably have attributed to the clear-headed, or French, side of me being uppermost for the moment—­may fairly claim record here, on its own merits.  Unlikely as it may seem, I had now actually groped my way to the root of the matter at last.  All I wanted was a hint to guide me in the right direction at starting.  Before another day had passed over my head, that hint was given me by one of the company who had been present at the birthday feast!

With the plan of proceeding which I now had in view, it was first necessary to possess the complete list of the guests.  This I could easily obtain from Gabriel Betteredge.  I determined to go back to Yorkshire on that day, and to begin my contemplated investigation the next morning.

It was just too late to start by the train which left London before noon.  There was no alternative but to wait, nearly three hours, for the departure of the next train.  Was there anything I could do in London, which might usefully occupy this interval of time?

My thoughts went back again obstinately to the birthday dinner.