With the heliograph signalling is effected by means of mirrors, which are so placed as to reflect the sun’s rays on to a distant station. The distance which these signals can be read varies according to the state of the atmosphere. Under favourable conditions signals can be read at a distance of seventy miles. The mirrors used are plane circular glasses and the system adopted is the Morse code.
So reads a description of the heliograph from a 1911 Will’s cigarette card. In the modern era of instant communications it is hard for us to comprehend how revolutionary to military communications the heliograph was. The ability to send information instantly over many miles changed the nature of the battlefield for commanders who for the first time had information on operations that was a few minutes rather than several hours old. In the high and hot climates of the Indian frontier the heliograph became a minor game changer. I was therefore very happy to add a complete heliograph to my collection recently:We will be looking at this instrument over two posts, tonight we will look at the heliograph itself and tomorrow the case and the operation of the instrument. Henry Christopher Mance (1840–1926), of the British Government Persian Gulf Telegraph Department, developed the first widely accepted heliograph about 1869 while stationed at Karachi, in the Bombay Presidency in British India. Mance was familiar with heliotropes by their use for the Great India Survey. The Mance Heliograph was operated easily by one man, and since it weighed about seven pounds, the operator could readily carry the device and its tripod. The British Army tested the heliograph in India at a range of 35 miles with favorable results. During the Jowaki Afridi expedition sent by the British-Indian government in 1877, the heliograph was first tested in war. The simple and effective instrument that Mance invented was to be an important part of military communications for more than 60 years. The usefulness of heliographs was limited to daytimes with strong sunlight, but they were the most powerful type of visual signalling device known. In pre-radio times heliography was often the only means of communication that could span ranges of as much as 100 miles with a lightweight portable instrument. The leather case holds a number of components for the heliograph: This heliograph is the most common design available, the Mance Mk V which has a 5” signalling mirror. The heliograph has a main mirror for signalling, and a secondary, duplex, mirror that can be attached and used to throw the sunlight onto the main signalling mirror if the sun is not in the correct position:Spare mirrors are held in a circular metal tin, which also details the full set of spares to be carried with the heliograph:I believe this heliograph dates from the Second World War, although I can find no dates on any part of the instrument, the /|\ mark and the instrument identification is etched into the base of the heliograph:The back of the heliograph has a press button that moves the mirror fractionally out of alignment and thus allows the operator to send the dots and dashes of light needed to signal:The heliograph was a remarkably long lived instrument, being used by South African and Australian forces fighting the Germans in North Africa in the Second World War and was such a part of life in the Empire that there is even a poem by Kipling:
Now Jones had left his new-wed bride to keep his house in order,
And hied away to the Hurrum Hills above the Afghan border,
To sit on a rock with a heliograph;
but ere he left he taught His wife the working of the Code that sets the miles at naught.
And Love had made him very sage, as Nature made her fair;
So Cupid and Apollo linked , per heliograph, the pair.
At dawn, across the Hurrum Hills,
he flashed her counsel wise — At e’en, the dying sunset bore her husband’s homilies.
He warned her ‘gainst seductive youths in scarlet clad and gold,
As much as ‘gainst the blandishments paternal of the old;
But kept his gravest warnings for (hereby the ditty hangs)
That snowy-haired Lothario, Lieutenant-General Bangs.
‘Twas General Bangs, with Aide and Staff, who tittupped on the way,
When they beheld a heliograph tempestuously at play.
They thought of Border risings, and of stations sacked and burnt —
So stopped to take the message down — and this is whay they learnt —
“Dash dot dot, dot, dot dash, dot dash dot” twice. The General swore.
“Was ever General Officer addressed as ‘dear’ before?
“‘My Love,’ i’ faith! ‘My Duck,’ Gadzooks! ‘My darling popsy-wop!’
“Spirit of great Lord Wolseley, who is on that mountaintop?”
The artless Aide-de-camp was mute; the gilded Staff were still,
As, dumb with pent-up mirth, they booked that message from the hill;
For clear as summer lightning-flare, the husband’s warning ran: —
“Don’t dance or ride with General Bangs — a most immoral man.”
[At dawn, across the Hurrum Hills, he flashed her counsel wise —
But, howsoever Love be blind, the world at large hath eyes.]
With damnatory dot and dash he heliographed his wife
Some interesting details of the General’s private life.
The artless Aide-de-camp was mute, the shining Staff were still,
And red and ever redder grew the General’s shaven gill.
And this is what he said at last (his feelings matter not): —
“I think we’ve tapped a private line. Hi! Threes about there! Trot!”
All honour unto Bangs, for ne’er did Jones thereafter know
By word or act official who read off that helio.
But the tale is on the Frontier, and from Michni to Mooltan
They know the worthy General as “that most immoral man.”