Campanile - Expo Paris 1889

The public stops at the third platform, i.e. at 276.13 metres. Above this, various rooms have been reserved for scientific experiments and for a small private flat that Mr. Eiffel intends to live in sometimes.

This end part of the Tower is formed by four lattice caissons oriented along the diagonals of the square section of the Tower. These arches support the lighthouse, which can be accessed by the people in charge of the lighting service via a small winding staircase mounted in the middle of the metal arches.

Three laboratories are installed in this bell tower.

One is devoted to astronomy.

The second, whose recording devices are connected to the central meteorological office, is intended for physics and meteorology; Messrs Mascart and Cornu believe they will benefit greatly from it for the study of the atmosphere.

The third is reserved for biology and micrographic studies of the air. Organised by Doctor Hénocque, it will not be the least useful to science.

The Lighthouse. - The lighthouse of the Tower has a power equal to that of the first class lights established on the coasts of France for the service of the Navy.

In the calculations for the establishment, the lighting of the quays of Rouen was taken as a term of comparison, for which a focus fixed at a height of 13 metres, and with an intensity of 24 amperes, sufficiently illuminated a circle of 130 metres in diameter.

As for the Tower, the distance from the focus to the centre of the figure was about ten times greater than in Rouen, so a focus was needed that was a hundred times more powerful; but as the absorption by the atmosphere was also taken into account, the light source had to be 123 X 24, i.e. 3,000 amps. Up to now, only a practical maximum of 90 amperes had been obtained with a single lantern; 33 lamps were therefore needed to give the maximum. Instead, 48 lamps of unequal intensity were installed around the upper lantern, in three stages, illuminating three concentric areas.

The lighthouse is fixed, but the glass plates in front of the lights are mobile and rotate by means of a clockwork mechanism; these glass plates are blue, white and red, and the national colours are thus slowly carried across the immense horizon every night.

The lighthouse cannot be seen directly from the exhibition grounds. It can only be seen from a distance of fifteen hundred metres, i.e. from the Place de la Concorde, the Invalides or the Champs-Elysées.

A force of 500 horses was necessary for this production. It is, like all the machines of the lifts, in the basement of the pile n° 3.

The projectors. - Independently of this lighthouse which, by a very curious system of revolving glasses, spreads its tricolour lights all around Paris on the different points of the surface of a circle of 70 kilometres radius, two high-powered projectors allow to launch, during the night, beams of light on the monuments of Paris.

These electric projectors are no less than 90 centimetres in diameter. They are placed at a height of 290 metres and on clear nights they reach a distance of about 10 kilometres. They are identical to the devices used by the battleships of our fleet. Their luminous power is equal to that of 10,000 Carcel beaks and the total intensity of their light beam is equivalent to eight million carcels.

By concentrating the two beams on the same object an intensity of sixteen million carcels can be reached.
Electricians, employed during the day to clean the apparatus, direct the light every evening, from eight to eleven o'clock, on the highest points of Paris or the neighbouring departments.
These grandiose experiments are assured of considerable success with the public.

The flag. - Above the dome of the lighthouse there is still a small terrace of 1.40 metres in diameter with a metal railing. It is reached by an internal staircase built into a 0.80 centimetre pipe similar to the chimneys on liners. Along the length of this pipe, rungs have been fixed which only allow the passage of one person. This staircase was built internally so as not to interfere with the projection of the lighthouse's rays.

This last terrace, which is 300 metres above the ground, is especially intended for anemometers and meteorological apparatus, which require complete isolation, and which must be placed out of the vicinity of any lateral obstacle.

It is certain that such a station will render the greatest services to science: it is a new proof of the practical utility of the Tower.
A flag 8 metres long and 6 metres wide has been fixed to a wooden post and surmounts this last terrace.

The Figaro reported, a few days after the flag was placed, that English tourists had been allowed to climb to the top of the Tower, and had torn off shreds of the flag as a souvenir of their ascent!

It was on Sunday, March 31, 1889, at 2:40 a.m., that Mr. Eiffel hoisted the flag on the top of the Tower to indicate that the work of raising it had been completed: the tricolour flag has flown ever since on the highest building that man has ever built.

This moving ceremony was accompanied by salvos of Ruggieri cannons, cannons that were placed on the third platform and that resonated shrilly in the iron frame.

The lightning rod. - The Académie des Sciences, upon completion of the Tower, congratulated M. Eiffel on the results he had achieved. It declared that any lightning rod would be useless at the top and would even hinder the planned experiments.

The Tower itself is a huge lightning rod protecting a very large space around it, because the metallic mass is in constant communication with the aquifer of the subsoil through the special conductors arranged along each pillar, as explained above.

Thanks to these perfect precautions, the interior of the building, together with the people inside, is absolutely safe from any accident caused by lightning.

© Guide Bleu du Figaro et du Petit Journal 1889