Both the compressors shown here are duplex or double-acting, but they differ in other features. One is actuated by steam direct, and the other is intended to be driven by a belt. The valves and much of the other mechanism of the compressors are constructed on the same principles as those of the steam-pumps made by the same company, which are too well known to require any description here. As the length of stroke of the pistons, in both the pumps and the compressors, is about the same under all ordinary variations of steam-pressure or load, much less clearance is needed for the steam-valves than would otherwise be necessary, — an important point in the construction of compressors. Any desired airpressure may be maintained by means of an automatic regulator, which opens or closes a valve in the steam-pipe. It may be added that these machines are as compact and simple in construction as is compatible with the uses for which they are intended; and they are not liable to get out of order, even when run at high speeds.

GARBAGE CREMATION.

WE had occasion a year ago to describe the Engle furnace for the cremation on a large scale of a city's garbage. To-day we are able to show an illustration of a small furnace for the same use in private houses.

It is doubtless true that nature has its own way of transforming offensive unsanitary matter into new forms in which it is no longer dangerous; but the application of fire can bring about in a few

THE ENGLE FIRE-CLOSET.

moments that which, if left to natural processes, would take weeks or months to accomplish.

The practice of cremation in place of burial is doubtless growing, and is each day gaining new adherents. A recent canvass of the opinions of the leading physicians of Philadelphia brought out the fact that the majority of them favored the fire method of disposal of human bodies, several of them taking occasion to point out that it all comes to the same thing in the end, the difference being only in the time consumed.

The Engle fire-closet is the application, on a somewhat smaller scale, of exactly the same principles contained in the garbage cremator described last year. By the use of two fires, one at either end of a small furnace, the smoke and gas evolved in consumption are destroyed, There is no escape of any offensive smell, and the furnace perfectly supplies the use intended, for the sanitary and economical destruction of all matters placed therein.

The advantages of such an apparatus as this are obvious. It is placed in a dwelling, where it is used for the reception and destruction of all garbage, as well as night-soil. It is especially useful in places of public resort, hotels, and restaurants, where a large num

ber of people congregate, and supplies the place in such institutions of an expensive and elaborate system and sewerage. It is in daily use in large collegiate institutions and public-school buildings of cities where no adequate system of drainage is in force, and is serviceable for the destruction of the waste and worthless matters produced by all manufacturing establishments.

The Engle fire-closet is in use in hospitals, for the burning of infected clothing, bedding, furniture, and other matter requiring to be destroyed, from patients suffering with contagious or infectious diseases. As an adjunct to the disinfecting and quarantine stations of cities and the general government, it is an auxiliary of importance.

The illustration shows the construction of an Engle fire-closet adapted for the use of a single family. The matter to be destroyed, both solid and liquid, is received directly through soil-pipes from closets above into the evaporating pans and on the garbage bars of the furnace. The flues into the chimney are kept open, and there is no escape of any smell or odor into the surrounding room; and at the proper time fire is applied, and the contents are destroyed. These fire-closets are constructed of steel, lined with fire tiles, with receiving pans adapted for the purpose required, and occupying a comparatively limited space. They are placed in convenient locations, usually in the lower part of the building, or in the cellar, where access can be had to a flue or chimney of moderate size. Being portable and easy to handle, they may be removed at any time to any other desirable site as the exigencies of the weather may require.

A NEW PROCESS OF PROTECTING IRON EFFECTUALLY AGAINST CORROSION.

THE following report on this process was made by Professor H. Haupt to the Franklin Institute of Philadelphia some time since:"For a period of more than ten years experiments have been made under the auspices of the Hydrogen Company of the United States to discover a simple, economical, and practical method of protecting iron and steel from all ordinary corrosive influences. A large number of patents were secured, and about $100,000 expended in the erection of plants at Washington, D.C., Newburg on the Hudson, and New York; and some of the results were of the most satisfactory character. Iron that had been treated by the processes referred to effectually resisted the action of nitromuriatic acid and other severe tests to which it was subjected, while untreated iron was immediately attacked by the acids and quickly destroyed.

"But, although many of the specimens thus treated gave very satisfactory results, others proved defective; and it became apparent to the contributors to the funds that the exact conditions as regards temperature, quality, and quantity of material employed, and duration of treatment, had not been so accurately determined that results could be duplicated with unerring certainty, an essential condition, without which no process could ever be made a commercial success.

"This explanation has been considered necessary to account for the fact that an industry which promised results of such extraordinary value to the public and to the parties financially interested should have been allowed to linger until the greater portion of the life of the original patents had expired.

"But persistency has at last been rewarded with success. The company succeeded in securing the services of a thoroughly practical and scientific engineer, chemist, and metallurgist, Dr. George W. Gesner, who was enabled to discern the defects of former treatments, and to remedy them successfully by new apparatus and processes, which have recently been patented; so that, while the old patents are still held by the company, they have to a great extent been superseded by more recent issues, under which operations now are and will hereafter be conducted.

when satisfactory, could not be duplicated under former management with certainty as to the result.

"All this is now changed; and the results are so uniform and certain, that, with a few hours of instruction in the manipulation of the apparatus, an ordinary laborer, with no technical education and with average intelligence, can secure results with entire uniformity.

"Dr. Gesner soon discerned that one of the chief defects in the former treatment arose from the fact that the steam superheated in a separate furnace, and conducted by pipes into the retort, was invariably cooled to the extent of several hundred degrees before admission, and came in contact with the heated iron at a much lower temperature.

"To remedy this defect and insure absolute uniformity of temperature between the iron and the superheated steam at the instant of contact, a peculiar but very simple form of superheater was devised, and inserted in the retort itself. The result was entirely satisfactory; and, after a number of experiments by him to determine the conditions necessary to insure the best treatment, the works were turned over to an employee, who has since operated them with uniform results.

"The plant now in operation is located at East Port Chester, near the extensive foundery of Abendroth Brothers, and consists of twelve vertical retorts with a capacity for the treatment of about twenty tons per day of the Gesner sanitary soil-pipe. The time required for each charge is about two hours.

After the pipes have been lowered into the retorts by means of a traveller, the retorts are closed for about fifteen minutes, until the contents are heated to the proper temperature. Steam from a boiler at sixty pounds pressure is then introduced into the superheater, which it traverses, and from which it escapes at the temperature of the iron, upon which it acts for about one hour. A measured quantity of some hydrocarbon is then admitted with a jet of steam, followed again by a fixing-bath of superheated steam, which completes the process.

"The most extraordinary feature of the operation is that, as Professor Gesner positively asserts, there is no pressure in the retort, and no free explosive gases. The water-seals attached to the retorts show only slight oscillations, but not an inch of pressure; and when the covers are removed, and air admitted, there is no explosion, as there always is when free hydrogen or carbonic oxide are present, and as there always was before Professor Gesner took charge.

"The absence of pressure and of explosive gases is a proof that all the operations have been so nicely regulated as regards material used, quantity, and time of application, that a perfect absorption and union of the carbon, oxygen, and hydrogen with the iron has been effected.

The protection thus afforded to the iron is not a mere coating, like paint, but an actual conversion, to a greater or less depth, into a new material, just as, in the process of case-hardening, iron is converted into steel. When properly treated, this material does not seem to be detachable by pounding, bending, hammering, rolling, or heating. The pipes treated at Port Chester have been immersed in baths of dilute sulphuric acid, and exposed to the salt air for weeks without change, while untreated pipes were quickly covered with red oxide or with sulphate of iron.

The exact chemical composition of the material produced by this treatment has not been reported upon by Professor Gesner, but it is probably a carbide, hydride, and superoxide of iron. This would seem to be a necessary result, if, as is stated, the retorts when opened contained no free gases, neither hydrogen, oxygen, nor carbonic oxide. As these gases are necessarily formed, their disappearance can only be explained on the theory that they have combined with the iron, forming the three compounds of superoxide, plumbago, and the alloy of hydrogen and iron, for which Professor Gesner has proposed the name of 'hydron.'

exact conditions as to temperature, quantity, kind, duration, etc., to secure the best results, after which they can be duplicated indefinitely with any ordinary intelligence.

"The question is often asked, 'What is the effect of this treatment upon the tensile strength of the material?' This can only be answered by direct tests; but if the new material should not possess the tensile strength of the untreated iron, as in wires or rods, compensation can be secured by a slight increase in diameter. It is certain that in some specimens the treatment has increased the toughness and strength by the annealing process to which the material is subjected. Sheet iron of poor quality, that would break by bending, has been rendered tough and pliable.

"The cost of the process is said to be about one-fourth of that of galvanizing, while the durability under similar conditions promises to be greatly extended."

SUPPOSED SHOWERS OF METEORITES IN THE DESERT OF ATACAMA.

IT is now universally acknowledged, says a correspondent of Nature, that meteorites come from outer space, and that shootingstars, whatever they are, have an extra-terrestrial origin. It is further asserted that a meteoritic fireball and a shooting-star are only varieties of one phenomenon. Indeed, after it is once granted that a meteoritic fireball is produced by the passage through the terrestrial atmosphere of a dense body entering it with planetary velocity from without, and, that shooting-stars have an extra-terrestrial origin, it is a very fair assumption that a shooting-star is likewise a dense body rendered luminous during its atmospheric flight.

One great objection to this assertion is, that again and again showers of hundreds of thousands of shooting-stars have taken place, during which no heavy body has been observed to reach the earth's surface. The only known case of the arrival of a meteorite during a shooting-star shower was that of Mazapil, on Nov. 27, 1885, and that single coincidence may possibly be the result of accident. A sufficient explanation of this difficulty, however, is to be found in the small size of the individuals which produce the appearance of a shooting star shower. That the individuals are really minute is proved by the fact, that, while the total mass of a large swarm, like that producing the November meteors, is so small that there is no perceptible influence on the motion of the planets, the number of separate individuals is almost infinite. It is established that the Leonid swarm must be hundreds of millions of miles in length, and some hundreds of thousands of miles in thickness; and in the densest part of the Bielid swarm, passed through in 1885, the average distance of the individuals from each other was about twenty miles.

Further, it is now acknowledged that comets are themselves meteoritic swarms, and Mr. Lockyer has lately brought forward spectroscopic evidence that the fixed stars and the nebulæ are similar to comets in their constitution.

The question therefore immediately presents itself, is the size of a meteoritic shower, on reaching the earth's surface, ever comparable with that of a meteoritic swarm, as manifested by a shower of shooting-stars?

During the present century nearly three hundred meteoritic falls on the earth's surface have been observed, and on only a single date, namely, Aug. 25, 1865, has there been observed a fall on two distant parts of the earth on the same day. On that date stones fell at Aumale in Algeria, and at Sherghotty in India; but as the times of fall differed by about eight hours, and the stones arrived from different directions, it is more than probable that the coincidence of date was accidental.

The most convincing proof of the actuality of such showers is furnished by the masses which have been found in the valley of Toluca, in Mexico. Their existence had been chronicled as early as the year 1784, yet in 1856 it was still possible to collect as many as sixty-nine. Belonging, as they do, to a single type, they lead to the conviction that they are the result of a single shower. But the region over which the fall took place is not large: the length of it is said to have been only about fourteen miles.

It is a question of a certain amount of interest as to whether there is any evidence of the actual fall of a shower of meteorites over a large extent of the earth's surface. Such evidence has long been supposed to be furnished by the plentiful occurrence of meteorites in the Desert of Atacama, a term applied to that part of western South America which lies between the towns of Copiapo and Cobija, about 330 miles distant from each other, and which extends inland as far as the Indian hamlet of Antofagasta, about 180 miles from the coast.

The generally received impression as to the occurrence of meteorites in this desert is well illustrated by the following statement of M. Darlu of Valparaiso, read to the French Academy of Sciences in 1845:

"For the last two years I have made observations of shootingstars during the nights of Nov. 11-15, without remarking a greater number than at other times. I was led to make these observations by the fact that in the Desert of Atacama, which begins at Copiapo, meteorites are met with at every step. I have heard, also, from one who is worthy of trust, that in the Argentine Republic, near Santiago del Estero, there is, so to say, a forest of enormous meteorites, the iron of which is employed by the inhabitants."

A study of the literature indicates that “the forest of enormous meteorites" near Santiago del Estero, understood by Darlu as significative of infinity of number, is really a free translation of a native statement "that there were several masses having the shape of huge trunks with deep roots," and that not more than four, or perhaps five, masses had really been seen in the Santiago locality at the time of Darlu's statement. There is a similar misunderstanding relative to the Atacama'masses: it is clearly proved, that, at a date long subsequent to 1845, the desert was virtually untrodden and unexplored. In Darlu's time it was only crossed along definite tracks by Indians travelling between San Pedro de Atacama and Copiapo, and between the inland Antofagasta and the coast. In fact, it is established that the only Atacama meteorites then in circulation were all got from a single small area, three or four leagues in length, in the neighborhood of Imilac, one of the few watering-places on the track between San Pedro and Copiapo.

Since that time the discovery of rich silver-mines in the centre of the desert, and the working of the nitrate deposits, have led to vast changes; the desert has been more or less closely examined, and other meteoritic masses have been found. Still, the number of meteorites yet discovered, distinct either in mineralogical characters or locality, is shown to be, at most, thirteen.

One of them, Lutschaunig, is distinct from all the rest as being a chondritic stone; a second, Vaca Muerta, likewise differs from all the others in that it consists of nickel-iron and stony matter, both in large proportion; a third, Imilac, is a nickel-iron with cavities, like those of a sponge, filled with olivine; a fourth, Copiapo, is a nickel-iron with irregularly disposed angular enclosures of troilite and stony matter; the remaining nine consist of nickel-iron, virtually free from silicates, some of them showing no Widmanstätten figures when etched, others showing excellent figures more or less differing in character.

Now, in every meteoritic shower yet observed, the individuals which have fallen simultaneously have been found to belong to a common type. Hence it is reasonably certain that several distinct meteors are represented in the desert, and that the above masses are the result of several falls; and, this being accepted, the assertion of simultaneity of fall of two or more masses on the purely geographical ground that they have been found in the same desert, can be allowed no great weight.

It is thus clear that the meteorites of the Desert of Atacama afford absolutely no proof that enormous meteoritic showers have ever reached the earth's surface.

The general dryness of the air of the desert, and the rarity of rain, have been sufficient to insure the preservation of masses which have fallen in the course of many centuries unto a time when an exploration of a large extent of the desert has taken place.

That the meteoritic masses are far from being so plentiful as has been imagined is conclusively proved by the experience of Mr. George Hicks, one of the earliest explorers of the 23d and 24th parallels. Although much interested in their occurrence, he never found a

THE PULSION TELEPHONE.

A CURIOUS scene was enacted recently at a place called Child's Hill, on the Midland Railway, near London, England. What took place there, as vouched for by Engineering, was as follows. A party of gentlemen alighted from the train and ascended the embankment. Here one of them reached up to a wire stretched along the telegraph poles, and, placing the crown of his hat flat against it, he commenced a conversation with some unseen correspondent. The answers to his questions and remarks came back quite audibly to the group gathered around him, while those who felt sceptical as to the reality of what was being enacted before them, removed to a distance, and, pressing the wire against their ears and cheekbones, heard the return messages for themselves. After some desultory conversation, the unknown speaker was asked to give a good shout, and in reply he jodelled with such vigor that a boy plodding his way along the cutting, at the opposite side of both up and down lines, looked up with amazement. He was at least eighty or one hundred feet distant, and yet he evidently heard the yell transmitted along the wire and received into the crown of an ordinary silk hat. It was quite impossible that he should have caught the original sound, for it was uttered in a cabin built on the side of the line at the Welsh Harp station, more than a mile away, and probably was not directly audible for one hundred yards. Those who were on the embankment knew that it was transmitted by means of a new mechanical telephone, for they had already listened to the same voice at Finchley-road station, which is 31 miles from the Welsh Harp.

When every one had satisfied himself that spoken words, whistling, and musical sounds could be received without special apparatus, the party re-entered the train, and went on to the Welsh Harp station, where they found several lines erected in the grounds of the local hotel. One of the lines starts from a small cabin in the grounds; it then proceeds to a post on the margin of the lake, and goes right across to a hut on the opposite bank. The distance is between a fourth and a third of a mile; and as this wire is not particularly tight, and only starts at a height of about ten feet above the water, it will be readily understood that it must lie for nearly its entire length in the mud which forms the bed of the lake. Another line traverses the gardens; its supports are formed by branches of trees, around several of which it is wound three times, and is then led off at an angle to its original direction. In another instance a row of statues are made to carry a line, which is laid upon any part of them which furnishes a convenient guide. This line is so slack that it can be bent into S form by the thumb and forefinger. The very various circumstances appeared, however, to make but little difference to the instruments, and in all cases conversation could be carried on with the greatest ease, and often could be heard a foot or two away from the receiver.

The instrument by which these curiously constructed lines were made to give such remarkable results is the property of the British Pulsion Telephone Company. It is the invention of Mr. Lemuel Mellett of Newton, Mass., and already several hundred instruments are at work in Boston and elsewhere. The construction is so exceedingly simple, that one is filled with wonder that it can effect so much. The receiver, which also acts as a transmitter, consists of a wooden case, divided into two parts by a metallic diaphragm held by a clip-ring and screws. In the centre of the diaphragm is a hole through which there passes the line wire, having at its end a button to take the pull. So far there is no special novelty to distinguish the telephone from the old pill-box and string. The new feature consists in a set of resonators placed over the diaphragm to re-enforce its vibrations. These resonators may be made in many different forms; those used on this occasion are spiral springs of various lengths, and made from wire of different gauges. One set of springs is festooned between the screws which hold the diaphragm, while others are held at one end only, and project upwards and inwards within the case. These resonators are chosen experimentally of such dimensions that each will be set into vibration by some one or more of the tones which are usually

found in the human voice. Consequently the faintest vocal tremor imparted to the disk is immediately taken up by them, and immensely magnified. This is done both at the transmitting and receiving ends, the result being that the wire is put into intense molecular vibration of a hitherto unappreciated character. It is evidently not merely lateral vibration, like that of a guitar string, for such motion would certainly be damped in the wire laid in the lake; it would also greatly suffer in the case of a span strung so slackly that at the centre it rests for many feet on the ground, yet such a span was shown to work reasonably well. It is evident, however, that the vibration is not purely longitudinal, for if it were it should be transmitted through a coil of wire flung loosely on the ground; and this, we understand, is not the case. It would, however, be a waste of time to try and formulate a theory apart from experimental investigation. What principally concerns us now is the fact that a mechanical telephone has been constructed, which will speak with absolute distinctness for three and a half miles, and which is simple, cheap, and, most important of all, free from induction. It is easily conceivable that its performances may be much improved; new forms of resonators may be found that have a nearer affinity to the tones of the voice than those already tried. Two vocal chords form the source of all the sounds we can utter, even if we be as gifted as Patti, and it seems possible that some material may be found more nearly allied to their action than wire helices. Although these can vibrate in harmony with the tones of human language, they have not the same quality of sound, and the metallic resonance which they impart to the articulation they transmit is not altogether an improvement.

HEALTH MATTERS.

Preventive Inoculation for Yellow-Fever.

WE are indebted to the Medical Record for the following translation of a report which was presented to the Academy of Sciences, Paris, by Dr. Domingos Freire, professor of organic chemistry and biology in the faculty of medicine of Rio de Janeiro, Brazil.

The epidemic of yellow-fever that developed in Rio de Janeiro in 1888 and 1889, and which propagated itself in several other places in the interior of Brazil, has been the means of demonstrating for the fourth time the value of inoculations by means of the attenuated microbe of yellow-fever. The maximum of the epidemic was between the months of December and March, the first sporadic cases having appeared about the end of the month of May, 1888, and the last in June, 1889. During this period there were inoculated 3,570 people; to wit, 988 strangers and 2,582 Brazilians, divided thus: the city of Rio, 2,138; city of Campinas, 651; town of Vassouras, 199; city of Nicteroy, 166; city of Santos, 133; Desengano, a village of 425 inhabitants, 102; Serraria, a small town, 80; city of Rezende, 54; Cataguazes, a village of 2,000 inhabitants, 50. The disease swept with great intensity in all of these spots, and the vaccinations were made, for the most part, during the height of the epidemic.

Of the 2,582 Brazilians, there were 1,740 that should be added to the 988 strangers, as this figure embraces not only individuals coming from the interior and resident in the city of Rio for less than six years, — that is to say, non-acclimated,— but also children, who, according to our experience, are just as susceptible as the strangers themselves.

The rate per hundred of mortality among the vaccinated was 0.078 at Santos, at Rezende, at Serraria, and at Cataguazes, the immunity from the disease was absolute. . Here is the rate per cent from each locality: Rio, 0.98; Campinas, 0.46; Vassouras, 0.05; Nicteroy, 0.75; Santos, 0.00; Desengano, 0.09; Serraria, 0.00; Rezende, 0.00; Cataguazes, 0.00. The mortality from yellowfever among the non-vaccinated was 4,135, divided thus: city of Rio de Janeiro, 2,407 (this includes the dead from the Marine Hospital); Campinas, 812; Vassouras, 15; Nicteroy, 177; Santos, 650; Desengano, 221; Serraria, 21; Rezende, 11; Cataguazes, 20. Among the 4,135 there were about 2,800 strangers, of whom, 1,176 died in Rio (and 750 of these in the Marine Hospital), 63 at Nicteroy, 500 (about) at Santos, 300 (about) at Campinas, 7 at Desengano, 3 at Rezende, 3 at Vassouras.

Thus one-fourth of the deaths were among Brazilians who were

unaccustomed to the poison, inasmuch as they resided in localities where the epidemic appeared for the first time this year. In order to make the efficacy of the inoculations more marked, it suffices to remember the proportion established by M. Jemble in Senegal ; namely, that among the strangers who had been there from one to three years, 75 per 100 were attacked by yellow-fever, and 68.06 per hundred died.

Applying these facts to the vaccinated strangers, or the provincials who had from a few days' to three years' residence in the infected locality, the following results were obtained. At Rio were vaccinated 1,183 people under the above conditions, of whom at least 591 should have succumbed to the disease, but only 18 died. Thus 573 lives were saved. At Campinas, a city that never before had an epidemic of yellow-fever, and where the 651 inoculated might be considered as new arrivals, of whom 325 should have died, the unsuccessful inoculations were but 3. At Vassouras, 5 should have died; one only died, who was not a recent arrival. At Nicteroy the II strangers, under the conditions cited above, should have furnished five deaths; one only was a victim. At Santos, of 57 persons under the same conditions, 28 should have died, but the immunity from disease was absolute. At Desengano, the two unsuccessful inoculations were among strangers who had lived from six to eight years in the country. But in view of the fact that the disease obtained for the first time, all of the 102 persons inoculated were as susceptible as strangers who had just arrived. Among them 51 should have died. At Serraria, according to the main calculation, 39 should have died, whereas the immunity from the disease was absolute. The same reflections apply to Rezende, where the 54 vaccinated should have furnished 27 deaths, and at Cataguazes, where the 50 vaccinated should have furnished 25 deaths, in view of the fact that the epidemic made its first appearance in these two localities; still the immunity was perfect, without exception.

There were vaccinated, between 1883 and 1889, 10,524 people, with a mortality of 0.04 per hundred.

Dr. Freire ceased vaccinating in 1887, owing to his trip to Europe and in the United States. The mortality from yellow-fever among the non-vaccinated, during the four epidemics mentioned above, was close on to seven thousand. It may be added, in closing, that all the results given have been authenticated by a large number of medical men, and municipal and police authorities. The vaccinations were made without fee. This succinct statement proves, without question, the truth of all the doctrines founded by the eminent master, M. Pasteur.

ANTIPYRINE HABIT. To the already long list of drugs the use of which, under proper restrictions, is both beneficial and proper in combating the various ills to which flesh is heir, but whose abuse becomes a curse to humanity, another has recently been added. Scarcely have we learned to properly use antipyrine, says the International Dental Journal, than the tocsin of alarm must be sounded against its abuse. The recent discovery of its value as a nerve-tonic places it on the list with morphine, chloral, cocaine, etc., so seductive is its gentle, soothing influence upon the overstrained nerves. Its victims are already found, especially among society women, whose nerves, strung up to a high pitch by the overwhelming demands of a winter season of gayety, seize eagerly upon any thing that will afford relief from the headaches and other disorders arising from prolonged fatigue and overtired nerves. So pleasing is the effect, that it is soon used for every trifling ill feeling, until the patient finds herself unable to live without it, and the fascinating “antipyrine habit" is formed. Properly used as a nerve-tonic, its effects are admirable, but abused, the victim becomes even more hopelessly entangled than the morphine or cocaine victim. The effects vary with the dose. In large doses it produces complete relaxation with loss of reflex action. In moderate doses, continued, it induces convulsions. As a stimulant its effect, is much like that of quinine.