expert

“He is speculating in railways,” said Lord Wilmore, “and as he is an expert chemist and physicist, he has invented a new system of telegraphy, which he is seeking to bring to perfection.”

A scientific expert would pronounce at once that this was drawn up on a suburban line, since nowhere save in the immediate vicinity of a great city could there be so quick a succession of points.

“I leave it to any expert in the world whether that is not the mark of his thumb.”

Sherlock Holmes, the well-known consulting expert, have each come to the conclusion that the grotesque series of incidents, which have ended in so tragic a fashion, arise from lunacy rather than from deliberate crime.