THE use of ultra-short waves in radio transmission for keeping police cars in touch with headquarters has proved itself of great value. A.R.P. necessities are increasing the demand for this system of communication. There are also a number of uses to which it can be usefully employed in connexion with switching on and off street lamps, water heaters during peak loads, calling air raid wardens and firemen and there would still be space in the high-frequency band for further applications, which are sure to be suggested within the next few years. Had the cost of these installations not been so high the progress made would probably have been more rapid. Sudden changes in the temperature will also encourage the installation of load-controlling equipment. One of its most useful applications is in connexion with fire-fighting. Experience gained in a recent local blackout shows that ordinary telephone communications can break down under the stress of a sudden emergency. The Electrician of August 18 says the Post Office has allotted a limited range of frequencies in the ultra-short wave band for police and fire-brigade purposes and that experimental work is being carried out by the Post Office in association with the Home Office to ascertain the possibility of developing local systems of this type. In dealing with emergencies, speed of communication is of the highest importance and wherever it is feasible to provide an effective means by which police, fire-brigade and ambulance headquarters can keep constantly in touch with their mobile units, this should be done.