The Rangitoto Light

New Zealand Graphic, Volume XXXVI, Issue 4, 27 January 1906, Page 30

The Rangitoto Light

A Marvellous Piece of Automatic Mechanism

Coming out from Home to New Zealand recently on one of the direct boats was one of those parties of emigrants which the fame of this salubrious country has from time to time attracted. The steamer was passing the first flashing light one meets on the outward trip.

and a small group of King Richard’s future subjects hailing mostly from inland towns was much impressed. It was a ten seconds’ Hash. One of the group full of sympathy and conversation opined that it was a very lonely spot, and further hazarded the opinion that the poor man must have a very hard billet “sitting up there, blowing that light out and lighting it again every little while like that.” The quartermaster, who happened to be the person addressed, when he recovered from accidentally swallowing his quid, agreed that it was a hard world, and hurried for’ard. The story is a true one, and, of course, such ignorance is deplorable; but to come nearer home, how many people know how the light is worked on Rangitoto, the lone sentinel of the Waitemata? In fact, there are a good many people who do not even know there is a light there at all. For years the end of the awkward reef which runs out from the island into the channel was marked by a high concrete tower visible for miles round in the day time—when it wasn’t needed; and lost in the gloom at night—when it was really wanted; Things move slowly in this sub-tropical climate, but at last the Harbour Board saw what shipping people had seen for years. They put a top on the tower, and installed a really line light, which Hashes every five seconds, and is visible for something like 15 miles. Anyone who has sailed in and out of the port

will understand what a boon this is to shipmasters. What sort of a light is it? Nine people out of ten couldn’t tell you. When one thinks of such a beacon one usually associates it with oil and wicks, and clockwork, and vigilant lighthouse-keepers, and all that

sort of tiring,, but the strange part about the Rangitoto tower is that it is lit with gas, and. stranger still, a human being doesn’t go near it for weeks at a time —six weeks at a stretch, to be precise. It is most fascinating to watch it Hash up out of the black night like a jewel, shine across the waters for five seconds, and then disappear as suddenly as it came. Five seconds of dark-

( barging the lighthouse cylinder. The hose.e > pci ally cased to prevent chafing on the rocks, is sent a-hore in the boat, and a connection is made between the cylinder in the tower and that on the punt. The hose can be seen lashed to the mooring hawser. in bad weather this is rather awkward, as the spot is so exposed.

ness follow, and then the flash returns with unfailing regularity. This goes on day and night, week in and week out. And the mechanism which performs this marvellous task is contained in a space not much bigger than a man’s hat! Like many other wonderful things, it is also

remarkably simple. In the lower part of the tower there is a large wrought iron cylinder about 10ft by 6ft full of gas, at a pressure of something like 2001 b to the square inch. A pipe leads from the top up to the lamp, in the under part of which is the regulating mechanism. which controls and cuts off the gas. It is bowl shaped, with a leather diaphragm at the top. Coming into this chamber at a presure the gas forces up the diaphragm and its attachment of levers, etc. An ingenious disposition of these levers, some springs, and a cam shuts off the entrance pipe qock when the diaphragm is inflated, and opens a cock in the pipe leading to the burner above. For five seconds the gas escapes into the burner, the diaphragm falls to its normal level, the tops are shut off and opened in the reverse order, and once more the regulating chamber fills with gas. It is very much like the regular breathing of a human being. As there is a pilot light similar to that used in the ordinary incandescent burner, the light can never go out —providing, of course, there are no unforeseen accidents. The gas used is made from crude petroleum similar to that used in the railway carriages, and is. in fact, made at the same place —alongside the Auckland railway station. It is much heavier and richer than other gases. Once every six weeks -the storing cylinder is re-filled and the lamp is cleaned. To take the gas down

from Auckland the Harbour Board has a special punt. Inside a house on board is a large cylinder similar to, but almost twice the size, of the one in the lighthouse. This is filled up alongside the Quay-street embankment, and on a favourable day is towed down to the channel by the tire-tloit. Anchoring of! the rocks, as close in as safety will allow, specially protected hose is connected to the cylinder on board, taken into the tower, and connected with the cylinder there, and the re charging is soon accomplished. Of course, it is simple enough in fine weather, but sometimes after a north-easter there is a nasty joggle on, and the work is then only accomplished -with much difficulty.

The tug-boat and punt anchored off the reef after the reservoir has been refilled. The charging cylinder is inside the house seen on the punt.

Pintfch’s patent lantern. This is a duplicate of the one at Rangitoto. and is stored by the llarbour Board in case of accident. The lantern is erected just as shown here, without further protection from the weather except a slight railing. When it is remembered that it is exposed to the full force of the howling north easters, which blow right in from the Pacific, it will he recognised that ventilation must be a delicate matter. The difficulty is got over by using a special kind of mineral gas made from crude petroleum, which. practically speaking, burns brighter the less fresh air you give it. The mechanism which regulates the flash, as explained in the letterpress, is all contained in the semispherical chamber at the base of the lantern.