[N320219], Technical Note, Thomas Alva Edison, May 2nd, 1887


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[N320219], Technical Note, Thomas Alva Edison, May 2nd, 1887

Editor's Notes

"preliminaze in wood tar in sealed glass tube wood tar being same nature as that from fibre I suppose a Thermometer can be sealed in tube-- the end should be drawn fine so air can be let out easy-- [drawing] fusible metal fibre will be kept seperated & also have a tension on them in carbonizing {Payne} It is probabl that with wood tar in sealed tubes and 10 hours run or less that 800 degs fahr can be reached & that there will be no more tar left in filiment to make a crust on surface to cause strain & cracks it is also doubtful if they will crook if not this will be an evidence there is little Rupert drop action on surface--" [Note: from here to end of book is undated but continues descriptions of experiments to be done by particular experimenters but see ] [drawing with labels "Thermom] and "Metal box in sand"] "Sealed tube-- Wood tar Thermom in 600 8 hours reading-- ditto-- quickly as possible a bunch of new stock 8 round-- about 100 in bundle, weighted with say copper to mold in solution" [these are in braces with line to "Oder Nos for Hamilton"] "Same as above only provided Rosin in tube which melts. Same as above lowers sulphur ditto finely powdered sugar [ditto lists: "phenol, Linseed oil, glycerine, mecury, Linseed loaded with asphalt, powdered asphalt, powdered Sulphide Potassium, aniline oil, acetic acid, saturated sol sugar, Parafine, Idiform, 2 pct sol of Caustic Potash, 2 pct sol of Sul Acid, pure water, Chlorine Water saturated Pentachloride phos 1 pct sol] "M Force takes Hamiltons order nos-- 25 are dipped in 62 sugar solution & run through preliminary to 900 in carbon boxes. Carbon laid in anthracite 10 meash but 1/16 of 80 mesh Cannel coal on bottom. Then given to Lawson to run through his final but not preliminary instead of 4 1/2 inch as now make equivalent to 5 1/2 inch to get 100 volts. 25 are to be run to 900 without dipping 25 are to be put in Lawsons forms in regular manner previously being dipped in 62-- 25 to be saved Then run through pump room as many as possible of the 25. afterwards what comes out all are to be tested for spots etc notes made about number bent & otherwise inferior & 10 of best are to be selected for curve ie order number Marshall take 30 Lamps Regulars but with new clamps 10 are to be run up on pump in regular way with exception that instead of running peg up as high as it will stand to run peg up little less than they do on regulars The next 10 are to be run up just as high as it is possible to go without arcing or melting clamp The remaining 10 are to be run up as high as possible in addition one to be allowed to burn 10 minutes or so at say 100 candles The object of the experiment is to consolidate the carbon on the pumps and prevent that portion of the drop in candle power due to increase of resistance which appears to take place in the first 2 or 3 hours at 80 candles I think that bringing the filament up much higher than usual which with new clamps is probably possible & holding the peg there some time that the fiiment will have the change taken out of it so when it goes to photometer room it will get a reading which will not change much after you will probably find that arcing will destroy some of your lamps so you better keep putting lamps on pumps until you get the requisite 10 for a curve keeping account of the number broken & how broken it took to get the 10-- you will select Reg 16 CP lamps for this test with the shank broken off & depostied by new process to inside wires-- If you find that arcing bothers you too much you can stop it but putting about 100 ohms resistance in circuit when you have the peg at the highest, the arc springs with greater difficulty when there is a resistance in circuit somewhat near that of the lamp-- It is probable that the deposit at the clamp should be somewhat thicker than would be necessary with the present way of working as a magnet will attract an arc I have a strong impression that it would be difficult to spring an arc if one of the magnets using on pump in Laboratory were used & powerfully energized-- perhaps you better use my pump for the experiments as they have magnets already on-- The great point is to bring the filiment up on the pumps far higher than is now usual in fact the highest attainable limit that is practicable with the use of every device to prevent arcing-- These 3 sets of lamps should be set up at 80 candles each and the drop in candle power taken every hour acurately this will give us the value if any of brining them up high on pumps & it may also effect their life for good or bad-- {End Marshall} [Deshler overstruck} Howell 5 Regular lamps to be put up at 80 candles a reading of candle power to be taken every hour & the change in resistance of the filiment taken acurately every hour The object of the experiment being to ascertain wht proportion of the drop in candle power is due to a change in the mere resistance of the filament-- by using a fresh lamp & putting in circuit a varying resistance The fall in CP from resistance can I suppose be ascertained I suppose 5 Lamps will be sufficient to give a correct result. Experiment No 2 Select 5 bulbs which have been blackened They should be of various shades from a slight blackening to a very much blackened on-- have Holzer4 carefully remove the inside part & broken carbon, then taken from a Regular lamp which has been test for volts CP & amperes the inside part & carbon & seal this in the blackened bulb-- tell him to be careful not to heat the bulb up where light comes through as this would remove some of the blackening the have them rexhausted & not run up very high on pump but just enough to get air out. Then at same volts & get CP-- The object of the experiment is to determine what proportion of the drop of CP is due to blackening-- These lamps should after you are through testing be mounted on a board & the loss on each plainly marked & kept in your museum for ruther reference by looking at the tint of a bulb & comparing one can pretty acurately determine the loss of CP by the blackening which will be useful in future experimenting if you don’t think 5 bulbs enough select a number as will give us a octave {End Howell} Martin Force-- 25 fibres of each kind 8 round of the different kinds of stock sent me by Payne & Hamilton Including Reg new stock mangrove to be tried bent round the hot bender in packed in about 40 mesh anthracite in Carbon boxes and these are to be given Lawson to be run through the full process after receving them from him they are to be secured to inside wires by deposit each filiment is to be cut 2 inches long after it is fully carbonized thus [drawing labeled "2 inches" and filiment as it comes from Lawson"] Each is to have an order number out of those of each order number that gets through pump room select 10 for a curve but have accounts kept of number of filiments that are good that comes out of the Carbonizing boxes number broken in depositing ditto pump room an important element to determine value of a new fibre is the breakage as well as the life-- These filiments are not to be treated in every manner but just run through in the old way this will determine their value independent of any treatment. I suppose you could string them on your paper sieve pieces for convenience & thus get the 25 in two boxes. These boxes should all be mixed & placed in varous parts of Lawsons mould-- [the following notes are written up by Mina in NM030003 5/7/87]] You are about to try the following experiments all of which will require several weeks time & very carful manipulation otherwise they will not be of very much value. The experiments are the bringing up bamboo filiments quickly & also gradually in liquids etc in sealed glass tubes thick enough to withstand the pressue which will insue from a temperature of 600 deg fahr-- These glass tubes should be about 1/8 of inch thick & 1 1/2 to 2 inches in diameter closed at one end by fusion like a test tube the other end should be open to permit the insertion of the filiments-- which must be secured in carbon or metal recepticle so filiment do not touch sides of glass tube & so they will not float to top in the liquid when a solid or powdered form becomes a liquid-- enough material should be used to cover the filiments entirely when the tube is at angle say 30 degs-- after the liquid powder etc is put in tube & everything ready it is to be taken to Joe Force & sealed the end being drawn out to a point so that when the experiment is finished the tip can be broken off to allow the escape of the gases slowly-- then the tube is to be cracked at point where it has full diameter the filiments taken out and soaked in a warm solvent of the material used for instance if asphalt was the material used then the filiments can be washed in considerable quantity of of Benzoil slightly warmed on sand bath. If Linseed oil a large quantity of Turpentine will dilute it so that filiments when taken out will have practically no Linseed oil on them & the temperature will evaporate the sugar then water will dissolve it-- always use a considerable quantity of water or other solvent to wash the filiments a chamber should be used which will hold say 3 to 6 tubes & heated by a gas stove or other means. A Fahr Thermometer should enter the chamber The bulb being amid the tubes so it will get same heat as they do the column should appear outside the chamber when mercury stands at 150 degreees The Thermometer should be capable of indicating up to 600 degrees a very long one is not necessary one about 12 inches long is sufficient & are not so expensive-- The chamber should be arranged so that the temperature can be regulated very nicely so that starting at 100 fahr it will go gradually up to 600 deg in 8 hours also be able to go to 600 inside of one hour as I desire to make some experiments rapid & slow-- should any tube explode the chamber will prevent the broken glass from coming in contact with the eyes-- The carbons to be used are regulr 8 x 13 !/2 with the shanks on same as now. About 25 filiments should be put in each tube except in the case where you put regular forms in then 3 can be put in each form & 3 forms used making 9 carbons. You can get instructions from me as to best method of putting the filiments together for placing in the tube after washing & drying the filiments they are to be placed in the little paper boxes with the Number marked on the box & also on a slip in the box-- each experiment should be given a number. Thus Hamilton Experiment No 1-- Variation No 6 The tube experiments being called No 1 Experiment & each tube in variation with a number-- There will be duplicate tubes in every experiment one of the tubes containing the same material as the other will be gradually run up in temperature from the temperature of the atmosphere to 600 degrees Fahr gradually during 8 hours-- While the other tube which is a duplicate wil be run up to 600 degrees in one hour or as near that as possible I shall require about 30 pairs of tubes all of which will be 1 12 inch diameter inside measurement 1/8 thick-- Have Mr Holzer order it immediately so as to have it by time your furnace is ready-- He will obtain for you a Thermometer anything relating to making furnace speak to me & I will have made-- all of the paper boxes conatining order numbers are to be delivered to me-- The following are the materials to be placedc in the tubes-- please see if we have them all if not make a list so they can be ordered immediately No 1-- Boiled Linseed Oil-- No 2-- Pure undiluted glycerine No 3 Mercury-- No 4 Phenol-- ie carbolic acid No 5 Parafine No 6 Wood Tar No 7 Powdered Rosin 60 mesh There should be enough powder put in tube so that when it melts it will cover the filiments fully No 8-- acetic acid glacial No 9-- 50 parts by weight of asphalt disolved in 50 parts by weight of Linseed oil-- No 10 powdered asphalt 60 mesh No 11 Aniline Oil-- No 12 powdered sugar this is sold in grocery under name of pulverized sugar & is very fine-- No 13 50 parts by weight of sugar & 50 parts water 14 pure water 15 Saturated Chlorine water 16-- 5 per cent solution of Caustic Potash in water 17 5 percent solution of Sulphuric acid in water 18- Idisform-- 19-- Flour of Sulphur 20 powdered fusible metal 10@20 mesh Formula 4 parts Bismuth 1 part Cadmium 2 parts of Lead 1 part of Tin These are previously fused together & then powdered I think it is brittle if not you can cut it up it melts about 175 Fahr-- See that we have a supply of material sufficient to make 4 or 5 times the quantity needed 21-- Trichloride of Antimony 22-- Anthracene 23 powdered sulphide of Potassium 24-- 5 percent solution of Chromic acid in water-- 25 5 percent solution of Nitric acid-- 26-- Water 93 parts Caustic Potash 5 parts pyrogallic acid 2 parts. 27. Chloride of Lime fresh 20 parts water 80 parts 28. Water 90 parts Hydrofluric acid 10 parts-- be very careful in handling the Hydrofluric acid not to get any on your fingers or body it makes ulcers but after dilution with water it is not dangerous I will probably give you other solutions in addition before the end of the experiment E" [see NM030003 for additional solutions]



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Thomas A. Edison Papers, School of Arts and Sciences, Rutgers University
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