of being the first of us to find this out, and, as you say, it bears every mark

of having been written by the other participant in last night’s mystery. I have

not had time to examine this room yet, but with your permission I shall do so

now.”

 

As he spoke, he whipped a tape measure and a large round magnifying glass from

his pocket. With these two implements he trotted noiselessly about the room,

sometimes stopping, occasionally kneeling, and once lying flat upon his face. So

engrossed was he with his occupation that he appeared to have forgotten our

presence, for he chattered away to himself under his breath the whole time,

keeping up a running fire of exclamations, groans, whistles, and little cries

suggestive of encouragement and of hope. As I watched him I was irresistibly

reminded of a pure-blooded well-trained foxhound as it dashes backwards and

forwards through the covert, whining in its eagerness, until it comes across the

lost scent. For twenty minutes or more he continued his researches, measuring

with the most exact care the distance between marks which were entirely

invisible to me, and occasionally applying his tape to the walls in an equally

incomprehensible manner. In one place he gathered up very carefully a little

pile of grey dust from the floor, and packed it away in an envelope. Finally, he

examined with his glass the word upon the wall, going over every letter of it

with the most minute exactness. This done, he appeared to be satisfied, for he

replaced his tape and his glass in his pocket.

 

“They say that genius is an infinite capacity for taking pains,” he remarked

with a smile. “It’s a very bad definition, but it does apply to detective work.”