No. 84. Chicago, III., Sept., 1904.

In several published description of receiving instruments for wireless outfits, one side of the coherer goes to the aerial wire and the other side to the earth. One side of the sensitive relay goes to the hammer of the decoherer, which also connects by contact point to the ground side of the coherer. When the relay operates, the heavy battery works the sounder and at the same time the same battery shunts through the windings of the decoherer and operates that simultaneously. Now, in view of these conditions, I do not see how one can get anything else than dots ", for just as soon as the decoherer operates the relay opens and the sounder stops, and just as soon, as the relay operates the deco-herer works simultaneously with the sounder. Please tell me how 6uch a system gives dots and dashes. I enclose sketch. J. R. B.

The circuit described is similar to several systems, among which is the Slaby-Arco, which is quite popular on both continents. The decoherer is a high-frequency hammer, as speedy as the quickest small vibrating bell mechanism. The stroke is adjustable.

The magnets of the Morse sounder and the decoherer are connected in parallel and are wound to the same resistance.

The decoherer gives a sharp blow against the coherer, and the weak relay-coherer battery circuit is broken just before the blow is made upon the coherer.

When the resistance of the coherer filings is broken down the weak battery is permitted to operate the relay, which in turn closes a local and stronger battery through the sounder and decoherer at the same time. When this is done the decoherer armature is drawn down, but in so doing the weak relay battery is opened off of the decoherer hammer, the relay flies back, and the decoherer and sounder, because of the break in circuit at the relay contact, return to their normal position, and it is this upward stroke of the decoherer which restores the coherer to its high resistance. The electrical energy radiating from the sending aerial in the form of etheral waves is collected on the receiving wire in the form of an alternating potential and conveyed to the coherer. When this tension affects the coherer, the relay operates as described. The sounder and de-coherer armatures start at the same time, and if the wave represents only a dot the sounder armature returns shortly after the decoherer acts. But while the decoherer is quick, the armature of the sounder is rendered sluggish by mechanical adjustments, which can be readily varied to suit, and when the series or train of interruptions representing a dash is being received the decoherer performs its function and springs back and forth many times before the sluggish armature of the sounder can rise. This feature presents itself most clearly in the operation of any inking device used in connection with the recording instruments."