This instrument, in fact, was little more than an enlargement of the ordinary telephone transmitter. It was made by attaching to an oblong of glass, constituting of course, an insulated base, two carbon supports, with cavities, and four cross-pieces, also of carbon, with pointed ends, fitting loosely into the cavities placed along the side of the two supports. The result was, this carbon being what electricians call "a high resistance" and the loose contact-points where the laterals rested making resistance still higher, that all vibration, however minute, jarred the points against their supports and varied resistance in proportion to the vibration itself. This, of course, produced a changing current in the "primary" of the induction coil, and was in turn reproduced, greatly magnified, in the "secondary" where with the help of a small watch-case receiver it could be easily heard. In other words, I acquired a mechanical sound-magnifier, a microphone, an instrument, of late called the dictaphone, which translates the lightest tap of a pencil-end into something which reached the ear with the force of a hammer-blow. And the whole thing, battery, coil, insulated wire, carbon bars and glass base, could be carried in its leather case or thrust under my coat as easily as a folded opera hat. It was equally easy, I found, to let it hang flat against the side wall of that rancid little _chambre particuliere_ which stood next to the room where most of those star-chamber conspiracies seemed to take place. My method of adjusting the microphone was quite simple. From the painted wooden partition I lifted down the gilt-framed picture of a bacchanalian lady whose semi-nudity disseminated the virtues of a champagne which I knew to be made from the refuse of the humble apple-evaporator. At the top-most edge of the square of dust where this picture had stood, I carefully screwed two L-hooks and on these hooks hung my microphone-base. Then I rehung the picture, leaving it there to screen my apparatus. My cloth-covered wires, which ran from this picture to the back of the worn leather couch against the wall, I very nicely concealed by pinning close under a stretch of gas pipe and poking in under the edge of the tattered brown linoleum. Yet it was only on the third evening of my mildly exhilarating occupation in that stuffy little _camera obscura_ that certain things occurred to rob my espionage of its impersonal and half-hearted excitement. I had ordered a bottle of _Chianti_ and gone into that room to all intents and purposes a diffident and maundering _bon-vivant_ looking for nothing more than a quiet corner wherein to doze. Yet for one long hour I had sat in that secret auditorium, with my watch-case receiver at my ear, while a garrulous quartette of strike-breakers enlarged on the beatitude of beating up a "cop" who had ill-used one of their number.