Why couldn't Mr.Sleuth's experiment wait till the morning?
She stared at him dubiously, but there was that in his face that made her at once afraid and pitiful.
It was a wild, eager, imploring look.
"Oh, certainly, sir; but you will find it very cold down here." "It seems most pleasantly warm," he observed, his voice full of relief, "warm and cosy, after my cold room upstairs." Warm and cosy?
Mrs.Bunting stared at him in amazement.

Nay, even that cheerless room at the top of the house must be far warmer and more cosy than this cold underground kitchen could possibly be.
"I'll make you a fire, sir.

We never use the grate, but it's in perfect order, for the first thing I did after I came into the house was to have the chimney swept.

It was terribly dirty.

It might have set the house on fire." Mrs.Bunting's housewifely instincts were roused.