At one time, eight carbon arc searchlights illuminated ancient Jerusalem, and a substantial portion at that, by casting their beams a great distance from the circular Christian Church of the Ascension on the Mount of Olives. Arculf (Arculfus), a Frankish bishop, perhaps of Prigueux, who visited and explored the Holy Land, accompanied by Peter, a Bergundian monk, who acted as a guide, reported the details and effects of these eight brilliant lights—and some others also.
The Catholic Encyclopedia gives us a little background on his marvelous report—as follows: “St. Bede relates (Hist. Eccles. Angl., V, 15) that Arculf, on his return from a pilgrimage to the Holy Land about 670 or 690, was cast by tempest on the shore of Scotland. He was hospitably received by Adamnan, the abbot of the island monastery of Iona, to whom he gave a detailed narrative of his travels to the Holy Land, with specifications and designs of the sanctuaries so precise that Adamnan, with aid from some extraneous sources, was able to produce a descriptive work in three books, dealing with Jerusalem, Bethlehem, the principal towns of Palestine, and Constantinople. Adamnan presented a copy of this work to Aldfrith, King of Northumbria in 698. It aims at giving a faithful account of what Arculf actually saw during his journey. As the latter 'joined the zeal of an antiquarian to the devotion of a pilgrim during his nine months’ stay in the Holy City, the work contains many curious details that might otherwise have never been chronicled.'”
The following two excerpts, from The Pilgrimage of Arculfus in the Holy Land (About the Year A.D. 670) was translated by the Rev. James R. MacPherson in 1895. He says: “The translation has been made as literal as possible in passages where the exact rendering was of any controversial or archaeological importance, as in the description of the sites and buildings.” Here are those two excerpts wherein Arculf continues to describe one of those buildings, a revered church on the Mount of Olives, and the effects of its bright searchlights as follows:
“In the western side of the church we have mentioned above [before], twice four windows have been formed high up with glazed shutters, and in these windows there burn as many lamps placed opposite them, within and close to them. These lamps hang in chains, and are so placed that each lamp may hang neither higher nor lower, but may be seen, as it were, fixed to its own window, opposite and close to which it is specially seen. The brightness of these lamps is so great that, as their light is copiously poured through the glass from the summit of the Mountain of Olivet, not only is the part of the mountain nearest the round basilica to the west illuminated, but also the lofty path which rises by steps up to the city of Jerusalem from the Valley of Josaphat, is clearly illuminated in a wonderful manner, even on dark nights; while the greater part of the city that lies nearest at hand on the opposite side is similarly illuminated by the same brightness. The effect of this brilliant and admirable coruscation of the eight great lamps shining by night from the holy mountain and from the site of the Lord's ascension, as Arculf related, is to pour into the hearts of the believing onlookers a greater eagerness of the Divine love, and to strike the mind with a certain fear along with vast inward compunction.”
And Arculfus went on to add: “This also we learned from the narrative of the sainted Arculf: That in that round church, besides the usual light, of the eight lamps mentioned above as shining within the church by night, there are usually added on the night of the Lord's Ascension almost innumerable other lamps, which by their terrible and admirable brightness, poured abundantly through the glass of the windows, not only illuminate the Mount of Olivet, but make it seem to be wholly on fire; while the whole city and the places in the neighborhood are also lit up.”