If in the near future an electric bell concealed about the person of a mau in the street is heard to ring, and he draws from his pocket a small ease, listens to it, and then hurries off, it must not hastily he assumed that he is mad. The probability will be that he livs just revived a message by wireless tele graphy.
Such things are not yet; but that they inay be is not so very wide an assumption from a demonstration which took' place recently at the Crystal Palace (London). In wireless telegraphy there are several Richmonds in the field. Best known is, of course, Marconi's system. But Sit William Preece has described to the British Association a system when he claims to be both earlier and simpler, and which may used for telephony as well as telegraphy, The first item at the Cafe Cha: tant of—the Crystal Palace was an exhibition of Mr. Rosenberg's system, The chief point of difference between this and Marconi's method is in a slight but important alteration in the construction of the coherer, which arrests, as they travel through the air, the Hertzian waves on which all wire. less telegraphy depends. O.herwise the apparatus is much the same, and for long distances Mr. Rose here depends on vertical poles, just as Marconi and Sir William Preece do. Mr. Rosenbers uses an induction coil with electricity from an accumu key-bourd is fitted to enable him to make or break the current at will, and the ines. sagais sent as uss] by means of anoseillator Itis taken at the required spot by strument containing tle coherer (a small brass tube Bled wit's nickel filings) ant a iver, from which the messuce may he printed ona tape in the usual This was demons to the interested audience at the Cafe Chantant to their complete satisfaction, Mr. Rosenbery's im is that he has tion he mentioned an interesting fact. When he leaves his cftice to lunch in a restaurant a couple of hundred yards off, he takes with him the little box containing the receiving apparatus. This he sets en the table beside him, "ud if the hell rings he knows that he is wanted at the office, even though his clerks mizht not beeware where he was; and he can receive a message from them.
Whether this introduces a new boon or a new terror to life cannot be hastily decided. Ir is not too much to suppose that before long the receiving apparatus might be improved and reduced in size, so that a man could easily carry it in' his pocket; and the range of the message muy he increased up to, say, half a-dozen miles. Then the business man may carry his receiver about with him and be in touch with his office all day. This would probably be an advantage, but, on the other hand, a jealous wife might insist on her husband carrying a receiver with him, so hat she mig' admonish him from time to time, which would hive disadvantages. The irritated husband would labour under a disability in that he could not talk back 5" he could only receive adviser, not return it, when the tinkling of the bell once more smote upon his conscience. Again, the system would be very useful for issuing instructions to employes and others away from headquarters; bat what if the messages became mixed? A re.
will not receive unless i tone with the sending instrument there is obviously great scape in this respect.—" Daily Teles
Text read from the printed page and cleaned; old type leaves the occasional error.