making, in order to prove that he was the original inventor; but during his examination before a Committee of the House of Commons, of which the great ex-Chancellor, then Mr. Brougham, was the assessor, the following question was proposed to him: "Do you mean to say that the area of a circle of two inches in diameter is only double that of a circle of only one inch in diameter? A. My opinion is, that it is double; your opinion may be that it is four times, but mine is that it is double." Here was a man, pretending to be a mathematician, who could not tell how to find the area of a circle; otherwise he would have known that the ratios of circles to each other are as the squares of their diameters. Through similar ignorance, Mr. Clegg nearly burned off his own nose; and a Mr. Lukin blew up a valuable furnace at Woolwich Dock-yard. True, it was surmised at the time that the two latter were more knaves than fools, when these accidents occurred to them; that their object was, to frighten the people in order to make a place for a Government inspector of gas. Be this as it may, the citizens of London were greatly afraid. They did not know how soon they might be blown to atoms in their beds; nay, there were not a few who predicted that some fine morning the whole city would-be converted into another Pompeii, or Herculaneum, the gas-pipes having exploded and laid all in ruins. This may seem exaggeration on our part, but it is not. The wonder would have been, had the people been otherwise than frightened, when Sir William Congreve (one of the candidates for the inspectorship) gave it as his deliberate opinion that mixing the gas with five-sixths of atmospheric air, and exploding it, the force was such that four hundred and eighty cubic feet of gas would exert the same power as a barrel of gunpowder, and if mixed with four-fifths, it was such that fifteen thousand feet of gas were equivalent in power to fifty-two and a quarter barrels of gunpowder. The Royal Society takes the matter in hand, and makes the terrible discovery that fourteen thousand feet of gas would explode with as much power as ten barrels of gunpowder! Such was the opinion of the most learned society in England at the time. No wonder that it was deemed serious enough to be brought before another Parliamentary Committee; and Sir Humphrey Davy, being summoned to give his opinion, stated that he conceived that the Society did not overrate the danger. We need hardly remark that the chemists of all

Europe were astonished, as well they might be; and that the reputation of Sir Humphrey suffered more by this "opinion" than it has gained since. The cause of the mistake, if such it may be regarded, was, that although several members of the Royal Society, as well as Davy, had studied chemistry, and doubtless understood it passing well, they had neglected to make the necessary experiments. It was in vain, however, that the gas manufacturers laughed at their "conclusions," as the author of Hudibras had done before them, and assured their customers that, with the most ordinary precautions, they had nothing to fear. How could the latter believe that the most learned body in England, with the famous Sir Humphrey Davy at its head, would deliberately frighten them; yet their own experience was entirely opposed to the opinion of the savans. They were not supposed to know that it was in ridicule of the same society that Butler had written his famous satire entitled "The Elephant in the Moon," more than two hundred years previously. And the same satire was perfectly applicable at the time of the "investigations" and "reports" referred to; for surely those, who mistook a mouse in their telescope for an elephant in the moon, were not a whit more credulous or silly than their descendants, who predicted the most frightful catastrophes from gas, because a Mr. Clegg so little understood its properties that he hurt his nose with it. In Butler's time, the Society had its Sir Humphrey, too-a sort of Supreme Court Judge, whose opinion served as a fiat to their "reports"

At all events, thus did the matter stand until Professor Faraday proved, by various experiments, that the calculations of his learned brethren were founded on false premises. It is worthy of remark in passing, that while the more recent part of this fuss was being made in England, in regard to the properties of gas, Mr. Charles Roome, who was then but the engineer (now President) of the Manhattan Gaslight Company of this city, was silently and unostentatiously making improvements in the manufacture of gas, which have since been adopted in Paris, as well as in London. This will seem all the more creditable to our fellow-citizen,

when it is borne in mind what serious inconvenience he had to labor under in comparison with those placed in corresponding positions in the principal cities of the old world. In the first place, the latter had an experience of eight years before we had any gas in this country, London having been lighted with gas in 1814; whereas New York was not lighted until 1823-4. It would be seen that the experience in England was much longer, were we to take into account the fact that so early as 1802, gas-lights were used at Bolton and at Watts's foundry, in Birmingham.

The gas manufacturers of England had within their reach all the facilities that science could afford; the accumulated treasures of the best scientific institutions in the world were open to them. It was otherwise with Mr. Roome. The scientific institutions of America, even so recently as twenty years ago, were, little more than in their embryo state. Such as they were, however, Mr. Roome derived little, if any, benefit from them; for he is a selfeducated, self-made man. His experiments, as well as his studies, were conducted in secret; generally without suitable apparatus. Even the coal, as we shall presently see, he had to get principally from England. Yet, so far as we are aware, he was the first to prove, to all who were willing to be convinced, the entire harmlessness of gas when the most ordinary precautions were taken to prevent explosions, and the little real similarity it has to gunpowder, let the Royal Society, Sir William Congreve, and even Sir Humphrey Davy, give any opinions they thought fit to the contrary.

Twenty or thirty years ago, as well as now, whatever created a sensation in England was pretty sure to produce a similar effect in this country. At any rate, the reports of the Royal Society startled the good people of New York. Not a few of them were willing to return to the use of candles, or even rush-lights, rather than be, as they were led to think, in constant danger of being blown to atoms, or engulfed into the bowels of the earth by the terrible gas! Mr. Roome made no display before learned societies, or anywhere else, but quietly wrote a pamphlet, in which he pointed out, in plain and popular language, the difference between gunpowder and gas, as follows:

"When gunpowder is burnt," says Mr. Roome, "about one-half of it is converted into an air, which is permanent at the atmospheric temperature and pressure. Thus one hundred pounds weight, which is a bar

rel of powder, will produce fifty pounds weight of air; or, in other words, a cubic foot of gunpowder will generate a permanent atmosphere two hundred and sixty times greater than itself; or, what amounts to the same, a barrel of gunpowder, weighing one hundred pounds, will produce two hundred and sixty barrels of air, or about two thousand six hundred gallons. The explosive power of this is easily ascertained; any intelligent chemist can prove it. Confined in a tube, and thus condensed that number of times, at the moment of its production, it is the pressure that discharges a ball; whereas, at liberty, it is a sudden blast of wind, acting on the surrounding atmosphere first, and the adjoining solids in succession, and continuing to act till a mean density of the general atmosphere is restored. Now, it is under circumstances nearly the reverse of all this that an explosion of a mixture of hydrogen and oxygen takes place; the result is a negative, not a positive quantity. The report is indeed nearly, if not quite, as loud as that produced by gunpowder: but it is more the effect of collapse than of the first slight expansion. In other words, the quantity of gas is lessened by an explosion, while it is largely increased in the case of gunpowder. Besides, it is only at a certain temperature and density that gas will explode at all; whereas gunpowder would cause a very great explosion, though in an atmosphere down to the freezing point -nay, below zero."

We believe that to the same gentleman is due the credit of having been the first to urge that copper is not suitable for gas pipes. When the warnings of science involve an outlay of money, they are too apt to be disregarded by those having the control of the latter. It was so in this case. But an accident or two occurred in New York, in 1839, which decided the point. A workman engaged in carrying copper gas pipes, which had been in use for several years, took it into his head to whistle with one of them. Not only did a violent explosion take place, but the unfortunate man's mouth and nose were so much lacerated that he died in a few hours. A similar accident occurred soon after, but fortunately without fatal result. Enough had been seen, however, to prove that Mr. Roome was right; his suggestions were adopted accordingly; and we have not heard that a single serious accident has occurred in the city since, except as the result of the most culpable negligence.*

We find these cases and their results noticed in the French Année Scientifique for 1861, the writer giving a full and interesting explanation of the cause and character of the explosion; and concluding with the statement that iron has been almost universally substituted for the copper, and consequently that no such explosive substance has since been found. "Au, cuivre primitivement employé en Amérique pour former les tuyaux de conduite du gas de l'éclairage, on a presque partout aujourd'hui substitué le fer. Or, le gas de l'éclairage ne produit pas, en agissant sur le fer, de composé fulminant analogue à ceux dont nous venons de nous occuper. Aussi depuit cette époque, l'occasion ne s'est-elle plus offerte, en Amérique, de retrouver ce singulier produit. Par son contact avec le plomb, le gas de l'éclairage ne fournit pas non plus le composé qui nous occupe."-Année Scientifique, p. 154.

Before we return from this digression, to note some of the improvements made in recent years-and nowhere more than in New York-in the manufacture of coal gas, we will make an observation or two on the generally received opinion, that gas-light is a modern discovery. In this, as in most other cases, we are too apt to contrast our own knowledge with the ignorance of our ancestors. If we stopped at this, it must be confessed that we should not be much in the wrong; but when we extend the comparison beyond the Goths, Huns, and Celts, to the great nations of antiquity, we find a different state of facts. There is good reason to believe that not only the ancient Egyptians and Hindoos, but also the ancient Peruvians and Mexicans, made use of some of the inflammable gases for heating, as well as for lighting purposes. That the Chinese had done so thousands of years before Mr. Murdock was born, is no longer a matter of merc conjecture. The fact is now as indisputable as the existence of their Great Wall. Humboldt tells us that carburetted hydrogen had been used in the province of Ste-tschuan for several thousand years; and that it was so far under control, that it was carried about in bamboo canes, to be used as occasion required, the same as a candle or a lamp.* Guy-Lussac and Professor Adelung, and several other scientific men of equal eminence, were of opinion that it was the occasional ignition of these natural gases which gave rise to the sun worship of the East, it being well known that deposits of petroleum, or naphtha, furnish gases which issue in streams from fissures in the earth, and which are ignited by various means, including lightning or electricity. Almost everybody, who has resided in the neighborhood of coal mines, has observed phenomena of this kind. Dr. Henry, of Edinburgh, in speaking of the "fire damp," so much dreaded by colliers, informs us that, from an old unwrought seam at Wallsend colliery, "a discharge of this gas takes place through a four-inch metallic pipe of two cubic feet per second. The pipe is carried up as high as the head gear above the shaft, and from its orifice issues, with a roaring sound, the stream of gas, which, having been ignited, forms a flag of flame seven or eight feet in length, conspicuous by day, and at night illuminating the whole neighborhood."

Not only have fewer accidents occurred in this country

Cosmos, vol. i., p. 217.