Mjw-if'w """"V "vfPpfc i 16 THE PITTSBURG- DISPATCH SUNDAY, MAY 15, 1892. TESLA'SJEW LIGHT, Its Success Largely Due to a New Product of "West em Pennsylvania. A EIYAL OF THE DIAMOND That Withstands the Terrific Elec trical Bombardment. CAEBOX CRYSTALLIZED AT LAST. It Makes a Lamp of Twentj Times Efficiency Now Beached the AND EE TOLUTIOXIZES 3TAXT INDUSTRIES of a coil, the carbon glowed with alight the intensity of which varied with 'the charaoter of the current. Teila found that a lamp filament cannot withstand the ef fects of currents of extreme frequener as it does those of steady currents, assuming that it be worked at the same luminous Inten sity. This means that for rapidly alternat ing currents the filament should be shorter and thicker. The xnoleoular bombardment that occurs with currents of high frequency is so se vere that Tesla had to go through a long course of experiments in order to discover a button of sufficient stability to stand the strain. He says: A W onderftil Ztew Material. Ofall the bodies tried there were two which withstood best diamond and carbor undum. These two showed up about equally, but the latter was preferable, for many reasons. As it is more than likely that this body is not generally known.I will venture to call your attention to it. It has been recent- -jggA ' lrsfe'Jggg DeniiiW TTAerii. rWHITTES TOR THE DISPATCH.! . ONE of the prominent y-CTS snres in the electrical I V i yr0TiA to-day " Nikola vances into new do mains of electrical science have excited the marvel of the world. Tesla holds that a phosphorescent glow is the light of the future, and he has already given good earnest of his prophecy. Last year he made a remarkable exposi tion of his researches before the American Institute of Electrical Engineers, nnrt when, a few months ago, he repeated his lecture, with many added features, before one of the most brilliant scientific audiences ever assembled, at the Royal Institution, London, the undemonstrative English were moved to a pitch of enthusiasm which nothing but intense convic tion and admiration could evoke. This feeling was markedly reflected in the criticisms of the English electrical papers, one of which described the keen interest Effect of Emery and Carborundum on Glast. ly produced by Mr. E. O. Acheson.of Monon jrahela City. Ta., TJ. S. A. It is Intended to replace ordinary diamond powder for pol ishing precious stones, etc.. and I have been informed that it accomplishes this object quite successfully. Carborundum can be ob tained in two forms in the form of "crys tals" and of powder. The former appear to the naked eye dark colored, but are very brilliant; the latter is of nearly the same color as ordinary diamond powder, but very much finer. When viewed under a micro scope the samples of crystal civen me did not appear to have any definite form, but rather resembled pieces or broken up egg coal of fine quality. The majority were opaque, but there are some which are trans parent and colored. The crystals are a kind of carbon containing some Impurities; they are extremely hard and withstand for a long time even an oxygen blast. When the blast is directed against them, tbey at first form a cake of some compactness, probably in consequence of tho fusion of impurities they contain. Tho mass withstands for a very long time tho blast without further fusion; but a slow carrying-oft or burning occurs, and finally,, a small quantity of a glass-like residue Is left, which, I suppose, is melted alumina. When compressed strongly they conduct verv well,but not as well as ordinary carbon. The powder, which is obtained from, the crystals In some way. Is practically non conducting, it anoras a magnmcem poiua ing material for stones. Like Edison's Search for the Filament. Te 'la's Xew Lamp; Section Shoving Button. "with which Mr. Tesla was watched throughout, as he adjusted his apparatus quivering with lightning-like discharges, and now lighted a vacuum tube by grasping it in his hand, now brought to incandes cence the filament of an ordinary lamp at tached by a single wire, then rendering the air in the interior of a large ring luminous with flame, or sending streams of light .. from wires stretched over the audience, rT3P?rceJ fatinating ot all, after electrify ing the whole space ol air between his table and an iron plate above him, waving a luminous tube in his hand totally uncon nected to any wire whatever. .America Is Just Learning the Truth. The full text of this lecture has just been received in this country, and the wonders that it unfolds are simply amazing. One cannot help the reflection while reading it that, had Tesla lived a hundred years ago, when the distinction between science and necromacy was not so well appreciated as it is to-day, the warmth with which his views have been received would be of a more ma terial form than that exhibited by his Lon don audiences. He speaks with the utmost confidence of the near approach of the time when lamps and motors will be run not only with one wire, but with no wire at all, and &t now incredible distances; there will eventually be no need to transmit power, as mere is an inexhaustible store 01 it, the ability to utilize which will have been developed at every point of the universe. He maintains that we have as yet but a very slight conception of the possibilities. 01 ariinctai iigut production; he believes that at least 20 times the efficiency of our present incandescent lamp can be obtained, and he calmly looks forward to obtaining light effects without the use of any vessel whatsoever, with air at ordinary pressure. To him the distribution of 100,000 volts to any distance within a thousand miles is "an easy matter." He speaks of a svstem in which the metal pipes are the insulators and the gas in them the conductors, and de scribes a cable with which telephoning across the Atlantic may became possible, if more advanced modes of transmitting in telligence shall not have rendered it un necessary. Ills Talk Sounds Extravagant. He speaks in the most matter of fact way of employing currents of a frequency of several millions per second, and takes 100, 000 volts through his body without mani festing the slightest inconvenience. But this modern necromancer knows just what lie is about and has the strong laith in his opinions which compels success. This is shown by his reply to a London electrician who asked how he came to dare to take such enormous currents through his body, con sidering that 1,500 to 2,000 volts are re garded as more than sufficient for the pur poses of the executioner. He said it was the result of a long debate in his mind. Reason and calculation showed him that such currents should not be dangerous to life any more than the vibrations of light are dangerous. The self-induction and irequeucy of alternation should be too great for any current to pass, and for a current to be dangerous a certain quantity must pass. He referred, as an illustration, to a thin diaphragm in a water pipe. "With to and fro piston strokes of considerable amplitude the diaphragm will be ruptured at once. With reduced strokes ot the same total energy the diapbrajrm will be less liable to rupture. Thus, said Tesla, it is with, vibra tory current, and he stretched forth his hand to the electrodes. Even fortified with this seductive logic the man who can thus plunje into dark and unknown depths un certain whether he will return, must be possessed of qualities which the world is apt to rate at a higher value than mere scientific faith. A Product or Local Importance. Such a brilliant record of invention as Tesla's lecture appeals alike to the scientist and the layman, but it bas a special interest to the readers of The Dispatcii, from the iact that it draws attention to the value of a new product, the development of which promises to be of great local importance. One characteristic form of the lamps with which JIr. Tesla illustrated his remarks was a bulb inclosing a button of carbon rest ing on the end oi a w ire or a filament The wire was screened by beine surrounded by a tube of aluminum, which forces the radiation to follow it to the but ton and not stream ofi sidewavs. "When the single conductor, which this lamp contained, was connected to one terminal I Having found carborundum, Tesla pro ceeded to test it with the same tenacity of purpose and hopefulness that Edison brought to bear on his experiments with the bamboo fiber that eventually gave the ideal filament for his incandescent lamp. After various tests with the crystals he turned his attention to the powder, which he made into a thick paint with tar. Through this he passed a lamp filament, rubbing ofi" most of the mixture afterward with a piece of chamois leather. He then held it over a hot plate until the tar evap orated and the coating became firm. This process was repeated until a certain thick ness of coating was obtained, and on the point of the coated filament he formed the button in the same manner. He is of opin ion that such a button of carborundum, properly prepared under great pressure, will withstand the effect of the bombard ment fully as well as anything heretofore known. The only difficulty is that the binding material gives wav, and the carborundum is slowly thrown off alter some time. This single objection, however, is likely to be soon overcome. Finding that it did not blacken the globe in the least Tesla sug gested its use for coating the filaments of ordinary incandescent lamps, and he thinks it even possible to produce thin threads or sticks of carborundum which will replace the ordinary filaments in an incandescent lamp. He found the carborundum coating more durable than other coatings, not onl y because the carborundum can withstand high degrees of heat, but also because it teemato unite with the carbon better than any other material yet tried. A coating of lroonift or any other oxide, for initanoe, It far more quickly destroyed. Making th Bubstanc Phosphorescent. Buttoni of diamond dust were next pre pared la the same way as those of carbor undum, which they approached very nearly in the matter of durability; but their bind ing piste gave way comparatively soon, owing, possibly to the size and irregularity oi the grains of the diamonds. Tesla then passes on to the consideration of an impor tant point in the determination of the future utilization of the material of whose possi bilities he has formed such a high estimate, its phosphorescing qualities. But, he first asks the question: Can a conductor phos phoresce What is there in sucn a body as a metal, for instance, that would deprive It of the quality of phosphorescence, nnless it is that property which oharaoterizes it as a conductor? For it is a fact that most of the phosphorescent bodies lose that quality when they are sufficiently heated to become more or less conducting. Then, if a metal be in a large measure, or perhaps entirely, deprived of that property, it should be capable of phosphorescence. "Therefore," ne says, and investigations made subsequent to the expression of the surmise indicate that he was guided by a true prophetic instinct, "it is quite possible that at some extremely high frequenoy, when behaving practically as a non-conductor, a metal or any other conductor might exhibit the quality of phosphor escence, even though it be entirely incapa ble of phosphorescing under the impact of a low-frequency discharge." The Great Secret He Has Uncorered. In connection with this Tesla offers a passing glimpse of a kaleidoscope, in which the characteristics of alternate currents or electrical impulses make fascinating and be wildering changes and combinations. He says: "By their help we may cause a body to emit more light, while at a certain mean temperature than it would emit if brought to that temperature by a steady supply; and, again, we may bring a body to a point of fusion and cause It to emit less light than when fused by the application of energy in ordinary ways. It all depends on how we supply the energy, and what kind of vibra tions we set up. In one case the vibrations are more, in the other less, adapted to affect our sense of vision." One cannot but be struck with the modesty of the distinguished inventor; be speaks of his discoveries as if they were mere matters of passing interest, instead of facts pregnant with a century of progress. Keverting to the tests for phosphores cence in carborundum, Tesla states that when a single electrode consisting ot a metal disc is covered with carborundum crystals, tne electrode is covered with an intense film of the whiteness of snow. This was found to be merely an effect of the bright surface of the crystals, for when an aluminum electrode was highly polished it exhibited more or less the same phenomenon. Tesla's Surmises Prove Correct. He says his experiments with the sam ples of crystals obtained were made "prin cipally because it would have been of special interest to find that they are capa ble of phosphorescence, on account of their being conducting. I could not produce pnosphorescence distinctly, but I must re mark that a decisive opinion cannot be formed until other experimenters have gone over the same ground." He speaks with the same degree of reserva tion of the tests with the powder. He found it would not phosphoresce, but says: "Still the tests with the powder are not conclu sive, because powdered carborundum proba bly does not behave like a phosphorescent sulphide, for example, which could be finely powdered without impairing the phosphor escence, but rather like powdered ruby or diamond; and, therefore, it would be neces sary, in order to make a decisive test, to obtain it in a large lump and polish up the surface." Here again he shows the prescient instinct of the true scientist. As a matter of fact, the phosphorescence of the later forms of carborundum, i. e., those manufactured some months after Tesla's samples, is now beyond question. The discovery of a ma terial which meets the requirements on which such Important and far-reaching Is sues depend Is destined to mark an epoch In the history of electrio lighting. Tho Qualities of Carborundum. Thus, muoh of the electrical utilization of the new product to which universal atten tion has been drawn by the distinction con ferred upon it by Tesla's investigation into the nature and qualities of this interesting material lead to the belief that eventually its greatest utilization will be in industries other than electrical. Its later form has the appearance of a greenish-yellow,glIsten-ing clndery mass. Under the microscope the crystals are found to be transparent, some are green, others yellow, blue or blaok, and the refractive power of the whole is so freat that the substance is of dazzling eauty. Its general formation is somewhat irregular, more or less resembling bort, or diamond powder, and the facets of its crystals are, as a rule, convex. its characteristics are extreme hardness, refractive power, insolubility and infusibll ity, and especially its high abrasive power. Its manufacture is in such an early stage that it is impossible yet to say where its greatest use will be found. It will unques tionably, however, oe in demand by diamond cutters, lapidaries and jewelers, dentists, valvegrinders, and for brass and optical work; in lact in all industries where abrad ers are used in the form of either diamond powder or emery. The cost of its produc tion is so low that the manufacturing in dustries will find themselves supplied with an abrasive material of the hardness of dia mond powder, and the general adaptability of emery powder, at a price relatively but little higher than that of emery, and practi cally much less. It Beats Emery Easily. A very interesting and conclusive test of its relative abrading power was made before the writer. On the end of one of two strips of class, about 1 inch wide by 214 inches long, was placed a quantity of fine emery powder, which had been moistened with water. The second piece of glass was then superposed on the first and at a given signal the two were vigorously rubbed together under pressure for 15 seconds. The emery was then washed off, and a corresponding quantity of carborundum powder of the same degree of fineness was placed on the other end of the glass, and the test was re peated for the same space of time. The dif ference in the sound of the action of the record of the respective work on the class. this impression wan more than verified: the emery had made a slight irregular cloudiness on the glass, but the carborundum had ren dered it opaque and had cut a well-defined path across it. The cut only hints at the effect produced. The crystals of carborundum are so hard that it is found impossible to reduce them to a powder by any grinding process, so a crushing force, such as is obtained in a stamping, mill is resorted to. To grade off the powder in the different degrees of fine ness, the crushed product is mixed with water and permitted to float for any re quired length of time, and then run off and allowed to settle in tanks. The coarseness or fineness of the powder is determined by the length of time allowed before running off. Will Supplant the Emery 'Wheels. In this way the grading can be most ac curately effeoted. The time allowed varies from four minutes in the coarse grades to two hours for the exceedingly fine ones. The crude material is made directly into wheels for machine shops. The abrading power of these wheels, judging bv tests lately made, will bring them immediately into active competition with emery wheels. One of our prominent manufacturers, in discussing recently the chances of success ful rivalry with emery said: "The field is large, Pittsburg alone uses 550,000 of emery wheels yearly, and the annual consumption of these wheels throughout the United States is at least 52,500,000." The economy of carborundum will be seen in the fact that it will do 25 per cent more work in the same length of time, and the class of labor employed In the use of these wheels is very expensive, running up to $4 a day. The saving, therefore, will he three fold, in labor, time and efficiency. In all probability the finer grades of carborundum will be used with cloth and paper, as emery powder now is. A short time ago some car borundum was submitted to a plate glass manufacturer. Testing the material In his office he decided it was too soft, but he afterward found when trying it in the factory that it was too hard, and ior this reason: Too Hard on Plate Glass. The finishing process of plate glass is started with sand, and then a coarse grade of emery powder is used. In the course of pressure and abrasion the emery particles break down, and become so reduced as to leave the glass in a high state of finish. The carborundum would not break down, but left the glass finished in a degree represent ed only by its original fineness, and the conservative glass finisher declined to countenance such a sweeping innovation, even though promised a powder of any degree of fineness he wished. In the grinding of valves and cocks' the present practice of using a coarse emery powder to begin with causes grooves to be left in the metal, and these have to be taken out by a second process. The actual cost ot the emery Is a small part of the total ex pense of the process. A man receiving 53 a day will scarcely use a pound of emery in two weeks. 'With carborundum this pro cess can be carried out at the first intention, and with an efficiency of 50 per cent in ex cess of the old process. Beyond this, it en ables the manufacturer to turn out a class of work, the cost of producing which by the ordinary emery method would be prohibi tive. Equal the Dentist's Diamond Wheels. One of the most effective uses of car borundum will be in the construction of points for dental engines for the excavation and grinding down of teeth. These points are already made in various sizes, and are commended by dentists with enthusiasm, and declared to be, when properly bound, equal in every respect to diamond wheels. The diamond wheel is a disc of copper charged with diamond powder, and when used it has to be kept continually wet. Another disadvantage is that as the fineness of polish produced on a tooth increases, the effectiveness of the abrading surface de creases, and the expenditure of additional time and labor becomes necessary. HOMES We fit them up in elegant style for LITTLE MONEY. WE CONTINUE To test THE DISPATCH as an advertising medium, and offer this fins OAK PARLOR STAND nIT1 IR, IE E To all purchasers of gio or more of FURNITURE or CARPETS. FAMILY REFFIfCERATORS -AND ICE CHESTS. We are Sole Agents in Pittsburg for the celebrated GURNEY PATENT HARDWOOD REFRIGERATORS. BABY CARRIAGES. The largest line in the city. Dainty and durable. Best Goods. Lowest Prices. ference in the sound of the action of the l.The difference between the ordinary and two powders was at once apparent, the car- Tthe carborundnm point was shown recently Dorunuuia seeming to nave at least twice tne grip ot the emery, on looting at the in a dentist's parlor in New York, where the dentist quietly substituted the latter for the former. The patient instantly noticed the change, and described it as the difference between "clean-cutting and jagged-sawing." Host people have had their share of bad quarter-of-au-hours with the dentist, and have a vivid recollection ot the sickeninc vibration of the cutting wheel. It is comfort ing to know that this form of martyrdom can now be banished. As showing to what ex tent small units grow into big industries, it may be stated here that there are 25,000 dentists in this country, each of whom uses on an average $10 worth of wheels a year, representing an expenditure of 5250,000. Other Oses of the Wonderful Material. For the cutting of rock crystals for lenses tests have shown carborundum to be especially effective, and for this purpose it is likely to completely supersede emery, which is now used. A singular character istic of carborundum is that its abrasive power is increased in proportion to the hardness of the material operated upon. For instance, while in lead plate cutting it would show n6 higher in efficiency than emery, in treating chilled iron or steel its superiority would be markedly manifest. Of course, the main interest of carborun dum to the scientist will be centered on its newly-found adaptability to the purposes of a wonderful discovery, and more especially will this be the case when crystals large enough to form an entire button are pro duced, which is easily conceivable. But enough has been said to justify its claim to be considered one of the most remarkable commercial products of recent years, and one which will eflect a revolution in a large number of industrial fields. Geoegb Hem Guy. CARPETS. Our sales are four times larger than any previous year. This speaks for itself. If you want a CAR PET, RUGS or CURTAINS come to. us. We will give you a square deal and save you money. We do this in order to find out which paper brings us the most patronage. In order to get the table FREE you must bring this page of this paper along. : CASH OB CREDIT. COMPLETE HOUSEFURNISHERS, CORNER TENTH STREET AND PENN AVENUE. mvl5 AKJOTHBH CVF IWT OFFICE DESKS -AT- Stevens' Large Supply Housa, iPiiis STEVENS CHAIR CO., All kinds and grades. CHEAPER THAN EVER. Quality and price are what boom onr trade. S SIXTH ST., PITTSBURG aplO-su M-aa .ss sss isk' ssaaii S: For 3o jpays Wlrttng to Introduce onr CRAYON PORTRAITS i same time ex- business and customers. wi have decided to make this SDecial Offer: Send ci a Cabinet Picture, Photo graph. TinUpe.Ambrot7pe orDafjnerotjpe of yonrself or any member of your FREE OF C1IAKGE, nroTlded Ton exhibit It to VSOT9 ?lrtWi aa mrrr1nt r4 nnp mvV And USA vniTV tnflnpnr in PPrififi(nt fntnro nnfrM. Tij s nnmA anrl ailrirowa fin hnik- nf n( rtra qnrt it. will Ha rt-nmt ft R-iVt ower. we make any change In picture jcra -wish, not Interfering with the likeness -.. v auj uau m vuicago. Andreas ail man to THS CSISCEHT C3AY0N CO., Opposite New German Tieatre, CHICAGO, ILL. P- 8. Wo will forfeltllOOOO to anyone sending us photo mnd not receirlng crayon nictnre r KfcE as per this offer. This offer Is bona-flde. apio 23-su IN MEN'S FINE CLOTHING We lead the world, or at least this section of it in the lavishness of our display, the extraordinary extent of our variety, the super iority of our styles, excellence of workmanship and low prices. r & r -3f -r OUR SPRING SHOWING Of suits for business and everyday wear exceeds any thing we or any other firm in this city ever attempted. It's " downright extrava gance to pay a big price for a business suit when we can show the same identical styles and goods you pay your tailor $20 to $25 for at $12 to $15. We don't care what you are looking for in a Spring Suit, bring your idea widi you, and we'll find its coun terpart in our matchless as sortment, or we'll show you somediing that you'll like so much better that you'll be more than satisfied. Our low prices and ster ling values bring us the suit trade of the city. 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Underwear. 200 dozen Men's fancy striped Shirts or Drawers, regular 50c goods, 34 CENTS. 300 dozen Men's fancy Balbriggan blurts or Drawers, 75c goods, 49 CENTS. $3.98. On MONDAY, TUESDAY and WEDNESDAY we will exhibit in our Cloak and Suit Parlor the newest styles of Paris, London and Vienna made costumes. sAVE INVITE ALL THE LADIESIS- To call and see these high-class novelties whether desiring to purchase or not. P 4 f tT 200 dozen superfine French Balbriggan fancy striped Shirts or Drawers, regular $1.25 grade, 74 CENTS. SHOE SENSED Entire spring stock ready for your selection. Shoes that are handsomer have yet to be .& Tnifif cnroc rnnr nrp nprrot can t be made, shoes that cost flttC locc ! rtmi- -iirj-itH-h ria T-tii?-i- rSkV W rtffnr fnr tliic woot- c-mk extra values in Calf Shoes for Men, Boys and Youths as follows: Men's Calf Bals and Congress $7.48 Boys' Calf in Button, Bals and.Congress. $1.48 Youths' Calf in Button, Bals and Congress. SJ.24 T - , T - g- You'll need a pair of Ox I A 8 J I l- 7k fords for the summer. Come MmrVlmJ 1 1 iJ this week early and get a pair of Dongola Oxfords, lace at 50 CENTS Mk V BB&fcrt, -tftjBft SjfirF GUSKYS Yw I if IN CHILDREN'S SUITS We are showing the most lovely assortment we ever had. Many styles here not to be seen in any other store in town. Hilts, Zouaves, Juniors, Sailors, etc. - $J6 HUSKY'S" z -1 - 5f,AiaS- Z j ba(w . -v-. .2vfte&if 4S AU'lUliialadlW'jtaikdtel-. jJLK4i sVjfeifei" Ti- - Jig ' femBrtiimfaafifff'