William wouldn’t divulge what his invention was, because, he said, he was afraid of the idea getting about before he took out the patent.  He merely told us it was a device which no man living could do without.  But he went so far as to show us the inner workings of his discovery (hereinafter referred to as It), which, not knowing what they were for, rather mystified us.  I know there was a small suction valve which involved the use of water, because William demonstrated to us one Sunday afternoon in the drawing-room.  He said afterwards that the unexpected deluge that broke over the politely interested faces gathered round him was merely due to a leakage in the valve, and he set to work to repair it at once.

At that time William always carried on his person a strange assortment of screws, metal discs, springs, bits of rubber and the like.  He pulled them out in showers when he took out his handkerchief; they dripped from him when he stood up.  I think he kept them about him for inspiration.

William completed It in a frenzy of enthusiasm.  He said that nothing now stood between him and a vast fortune, and in a mood of reckless generosity he promised us all shares, which certainly tended to deepen our interest in the invention.  Then he betook himself to the Patent Office.

I saw him the following day, and it occurred to me at once that all was not well with William.  For one thing he did not burst in unannounced with hair dishevelled, which seems to be the usual way for an inventor to come into a room; he entered slowly and sat down heavily.

‘Is anything wrong with the invention?’ I asked.

He pulled out his handkerchief and mopped his brow.  A metal disc fell out and rolled unheeded across the floor.

‘Nothing is wrong with it,’ he answered dully.

‘You don’t mean that some one else has thought of It before you?’

‘Most people seem to have thought of It.’  He paused and absently plucked off a stray piece of rubber from his coat sleeve.  ’It seems to have originated in America in 1880.  Then a large colony of German inventors applied for the patent; a body of Russians were imbued with the idea; several Scandinavians had variations of it.  It even seems to have filtered into the brain of certain West African tribes; and in 1918 a Czecho-Slovak——­’ He paused, overcome with emotion.

’But if It is a thing man can’t do without, why haven’t we heard of it?’ I demanded.

‘Men,’ replied William sadly, seem determined to do without It.  They don’t know what is good for them.’

Suddenly he raised his head with the light of enthusiasm in his eyes.  ’By the way, I was talking to a chap at the Patent Office who told me that there’s an enormous boom in inventing in this country just now.  Henry ought to get a good article out of it.’

As a matter of fact it was the only thing that ever was got out of the invention.