One year afterward, the inventor had seen Fourcroy, Prony, and the great scientists of his epoch. On the 28th of September, 1799, he took out a patent in which he gives a complete description of his thermo lamp, by means of which he produced a luminous gas, while at the same time manufacturing wood tar and pyroligneous or acetic acid. In this patent he mentions coal as proper to replace wood, and he explains his system with a visible emotion and singular ardor. In reading what he has written we are struck with that form of persuasion that does not permit of doubting that he foresaw the future in reserve for his system.
Unfortunately, Lebon could not devote all his time to his discovery. Being a government engineer, without money and fortune, he had to attend to his duties. He went as an ordinary engineer to Angouleme, but he did not forget his illuminating gas, and he strongly regretted Paris, which he termed "an incomparable focus of study." He devoted himself to mathematics and science, he made himself beloved by all, and his mind wandered far from his daily occupation. The engineer in chief soon complained of him, but a committee appointed to investigate the charges that had been made against him affirmed that he was free from any reproach. He was sent back to his post, but war was decimating the resources of France, and the republic, while Bonaparte was in Italy, no longer had any time to pay its engineers. Lebon wrote some pressing letters to the minister, asking for the sums due on his work, but all of them remained without reply. His wife went to Paris, but her applications were fruitless. She wrote herself to the minister the following letter, which exists in the archives of the School of Bridges and Roads:
"Liberty, equality, fraternity—Paris. 22 Messidor, year VII. of the French Republic, one and indivisible—the wife of Citizen Lebon to Citizen Minister of the Interior:
"It is neither alms nor a favor that I ask of you, it is justice. I have for two months been languishing at 120 leagues from my household. Do not, by further delay, force the father of a family, for want of means, to leave a state for which he has sacrificed everything. ... Have regard for our position, citizen. It is oppressive, and my demand is just. There is more than one motive to persuade me that my application will not be fruitless with a minister who makes it a law and duty for himself to be just.
"Greeting and esteem. Your devoted fellow-citizen,
"Madame Lebon, nee De Brambille."
In 1801, Lebon was called to Paris, as attache in the service of Blin, engineer in chief of pavements. He took a second patent—a true scientific memoir full of facts and ideas. It speaks of the numerous applications of illuminating gas and its mode of production, lays down the basis of the entire manufacture—furnaces, condensers, purifiers, gas burners. Nothing is forgotten, not even the steam engine and balloon. Lebon proposed to the government to construct an apparatus for heating and lighting the public buildings, but the offer was rejected. It was then that the unfortunate inventor, wearied by all his tentatives, fatigued by his thousands of vexations, made up his mind to have recourse to the public in order to convince it of the utility of his invention. He rented the hotel Seignelay, St. Dominique-St. Germain St., and invited the public thither. Here he arranged a gas apparatus, which distributed light and heat to all the rooms. He lighted the gardens with thousands of gas jets in the form of rosettes and flowers. A fountain was illuminated with the new gas, and the water that flowed from it seemed to be luminous. The crowd hastened from all parts and came to salute the new invention. Lebon, excited by this success, published a prospectus, a sort of profession of faith, a model of grandeur and sincerity, a true monument of astonishing foresight. He followed his gas into the future and saw it circulating through pipes, whence it threw light into all the streets of future capitals. We reproduce a few passages from this remarkable production:
"It is painful," says he, "and I experience the fact at this moment, to have extraordinary effects to announce. Those who have not seen cry out against the possibility, and those who have seen often judge of the facility of a discovery by what they have to conceive of its demonstration. If the difficulty is conquered, the merit of the inventor vanishes with it. I would rather destroy every idea of merit than allow the slightest appearance of mystery or charlatanism to exist.
"This aeriform principle is freed from those humid vapors that are so injurious and disagreeable to the organs of sight and smell, and of the soot which soils apartments. Purified to perfect transparency, it travels in the state of cold air, and is led by the smallest as well as frailest pipes, by conduits an inch square, formed in the plaster of ceilings or walls, and even tubes of gummed taffety would perfectly answer the purpose. Only the extremity of the tube, which puts the inflammable gas in contact with the air, and upon which the flame rests, should be of metal."
