The age-herald., 1900-03-19
SIGNALING BY nELIoGRAPH
Comprehensive Explanation of the System
 Used in War

Gen. A. w. Greedy in New York Times.
 From time to time the cable has brought to the world during the past two months the news that General Buffers column on Tugela river has been communicating with the besieged garrison at Ladysmith over the heads of the Boers.
 It may be a matter of general interest to know exactly how such communications have been held.
 In the evolution of signaling the flag has largely given way for day work to the heliograph-a movable mirror with an at- tached finger key which controls Its move ments and throws the image of the sun to the eye of the observer at the receiving station. It is true that the use of the heiograph is limited to bright days and hours of sunshine, but its powers of pene- tration and facility of action are such to relegate to the rear the flag when pos- sble. Through dust and smoke, so dense as to obscure all outlines at short dis tances, the heliograph flash is visible to the naked eye at distances of 20 or 90 miles. Under favorable conditions the sig nal corps has worked over ranges in Ari- zona of 20 to 80 miles with the greatest ease, and from S5 to 121 miles under favorable conditions of atmosphere and elevation. The extreme range of leng-distance helio- graphy has been determined by the signal corps of the American army through the professional labors of Captain William A. Gassford who transmitted messages in September, 1895, over an airline distance of 1SS miles, between Mount Ellen in Utah and Mount Uncompahgre. Colorado.
 The present heliograph is the outcome of Indo-English effort, although the American modern instrument is operated by different and what is believed to be improved methods. The African ranges worked over by the British signalmen, between the hills overlooking the Modder river and belong- uered Ladysmith probably vary from 35 to 45 miles, comparatively short ranges for Photographic work The English heliograph consists of movable mirror, in front of which is a shutter that Is alternately re- moved and replaced by means of an attach ed finger key. By means of a sight, the suns flash is by screw gear kept fixed on the distant station. When the serene is re- moved the flash reaches the receiving sta- tion, and its interruption is accomplished by replacing the screen in it's original po- sition.
 By sun flashes of varying lengths of dura- tion and of pauses of interruptions all the different letters of the alphabet and the numbers are indicated.
 In the British army the military signal book contains numerals which stand for certain short sentences, so at times quite a number of words can be sent by few numerals. This method insures secrecy of messages should the flashes be read by the enemy over whose heads in the Modder valley these messages to and from the be- leagured residents of Ladysmith have been transmitted.
 Naturally the a1ellograph is used only for day signaling, and 1t seems probable that most of the messages to and from Lady, smith have been transmitted in this man. ner, and during the daytime. At night, however over long ranges where the use of the ordinary lantern would not suffice for signaling, recourse must be had to eith- CT electrical balloons or searchldghts. Fifth CT system looks to the presence in the field of dynamo power for the production of electric light. The reports so far as receiv- ed are indefinite as to which, if either. of these methods have been used at night by the British army.