Morton-Wall · Source catalogue

A two-and-a-half-page note in the June 1871 number of the Journal of the Franklin Institute (Vol. LXI, 3rd series). Houston used a Ritchie (Boston) induction coil rated for a 6 inch spark in free air and tried different loads on the two poles of the secondary wire; his stated aim was 'increasing the quantity of the spark of the induction coil without greatly diminishing its length' [read: p.594]. First arrangement: one pole earthed by a copper wire to a gas pipe, the other pole wired to the large lecture table that held the coil (the table is an imperfectly insulated conductor, in 'partial connection with the earth' through gas and water pipes, not an insulated one; only the tin-still arrangements used conductors insulated on glass). The spark became thicker, shorter and silvery white 'as when a Leyden jar is placed in the path of the discharge'; long sparks could be drawn from the table and any metal within 8 or 9 ft, and on one occasion the gas was lit by a spark from the finger of a person standing on the floor. Second: one pole to the gas pipe, the other to a stove whose pipe joins a stove in the next room; the spark thickened, and sparks were drawn from the distant stove and from a small steam engine 'fully thirty feet' from the coil (the electrical path to the engine is not described in 1871; Houston's Jan 1876 account says the engine was 'also in metallic connection with the water-pipes' [read: research/files Houston 1876, OCR ~lines 4218-4225]); in one instance sparks were drawn in a room below from a wire connected to the table. Third: an improvised insulated conductor of old tin stills and percolators on large glass jars on one pole, gas pipe on the other, increased the 'quantity' of the spark. Fourth (neither pole earthed; this is the arrangement that gave the five-inch result, not the one-pole-earthed case): the tin-ware was divided into two roughly equal conductors, one on each pole (neither earthed): quantity rose but length fell greatly; making one conductor smaller and the other larger restored length without sensible loss of quantity, until with one conductor under one square foot a 'fine quantity spark of about five inches' (italic in the original) was obtained. Houston compares the connection to earthing one conductor (usually the negative) of a cylinder or plate frictional machine, and explains it as the table (an imperfectly insulated conductor) allowing 'rapid induction of electricity in the secondary wire by its rapid discharge'. He concludes that the maximum increase 'would seem' to come with one pole on an insulated conductor of several hundred square feet and the other earthed. That large conductor was not built or tested in the article. A slight shock at every break forced him to insulate the break-piece handle. Not stated: battery, primary current, condenser, break rate, dates, number of trials, assistants or witnesses, areas of table/stove/tin-ware (except the end point), spark lengths after the first three arrangements. Nothing was measured with an instrument: 'quantity' is judged by eye (thickness, colour, 'fine quantity spark'). The article has no figures, tables or equations and does not mention Morton, Wahl, the Stevens Institute or any earlier work. The signature footer on the first page misprints the issue as 'JULY, 1871'; the volume contents list it in June. LATER ACCOUNT BY THE INVENTOR (Jan 1876, about the 1871 work): 'sparks could be drawn from any metallic objects in the neighborhood of the coil, and, indeed, in adjoining rooms'; for the Dec 1875 repetition (with Thomson, ten cells) 'from all metallic objects in the same room with the coil, or in adjoining rooms' [read: research/files Houston 1876, OCR ~lines 4214, 4308]. So the wider reach in later retellings is partly Houston's own later wording, not only accretion; the retellings still differ in date (1872), person (Thomson) and 'continuous'. Caveat on the 1876 battery wording: 'One pole of the battery was placed in metallic connection with a gas pipe' and sparks 'between the platinum points of the coil' can be read as primary-side; the likelier reading (a repetition of the secondary arrangement) is a reading, not a fact.

Key claims

• Houston's stated aim was to increase the quantity of the induction-coil spark without greatly diminishing its length (p.594); the large-conductor proposal for 'maximum' quantity is in tension with that aim, since the large conductor shortens the spark.
• Earthing one secondary pole at a gas pipe and joining the other to a large imperfectly insulated conductor (the lecture table) makes the spark of a Ritchie coil thicker, shorter and silvery white, like a spark with a Leyden jar in circuit.
• While the coil runs in that arrangement, long sparks can be drawn from the table and from any metal object within eight or nine feet, and from a person's finger (lighting a gas jet). The lecture table was in partial earth connection through pipes.
• With one wire to the gas pipe and the other to a stove connected to a second stove, sparks could be drawn from the distant stove and from a small steam engine fully thirty feet from the coil.
• An improvised insulated conductor of tin stills and percolators on glass jars, joined to one pole with the other pole earthed, increases the 'quantity' of the spark.
• With an insulated conductor on each pole (neither earthed; the five-inch result belongs to this case only), making one conductor smaller and the other larger restores spark length without sensible loss of 'quantity', giving about a five inch quantity spark when the smaller conductor is under one square foot, on a coil whose free-air spark is six inches.
• The effect resembles earthing one conductor of a frictional (cylinder or plate) machine, which increases the quantity of electricity.
• The large conductor lets the secondary discharge rapidly, so more electricity is induced in it; maximum increase would 'seem' to come from an insulated conductor of several hundred square feet on one pole and earth on the other (proposed, not tested).

Relevance: The only paper in the folder that is actually about a coil connection, and the one the file name and the project turn on. It is an early (1871) record of loading an induction-coil secondary with a large conductor against ground, with stray sparks over 30 ft and a person acting as a conductor. It is observational and qualitative; the explanation is hedged by Houston himself ('probably', 'it would seem'). Published under Morton's editorship, in the same volume as Wahl's description of Morton's coil, but Houston does not refer to either.

Mainstream conflict: None stated by Houston. His term 'quantity' is the 1870s sense of amount of charge per discharge and is not measured here; his explanation (rapid discharge allows rapid induction) is qualitative. A modern reading (added capacitance at one secondary terminal, circuit closed through ground, much like a Leyden jar across the gap) is a reviewer's interpretation for Step 2, not in the document.

Describes a coil built by E. S. Ritchie of Boston for Prof. Henry Morton, President of the Stevens Institute of Technology, which Wahl says 'we believe to be the most powerful now existing'. Wahl credits Ritchie with the fundamental improvements that made the induction coil reliable, and says they were published freely and adopted by others 'in some cases with anything but an honorable acknowledgement'. Comparison: a coil for Prof. Pepper by Mr. App of London, about nine feet long, 150 miles of wire, nearly a ton, gave 29 inch sparks with about sixty cells for a while, 'soon failed' and was taken to pieces; Morton's coil has about 44 1/3 miles of wire (printed '44 1/3' on p.320; 234,100 ft / 5,280 = 44.3 miles [computed]; the 150 miles of the App coil is about three times as much wire for 29 in against 21 in), is 40 inches long, weighs about 250 lb, and gives 21 inch sparks from only three cells, in perfect condition after several months of constant use. Construction: iron-wire core (wires about 1/18 in thick [printed as a small fraction, 1/16 not excluded], uninsulated from each other, 14 lb); primary 200 ft of 0.1655 in wire (17 lb); secondary 234,100 ft (about 44 1/3 miles) of 0.007 in Lake Superior copper, silk covered, wound in Ritchie's layered spirals with paraffin paper (44 1/2 lb); glass bells and vulcanite spools between primary and secondary, tested 50 per cent stronger than a 21 inch spark would penetrate; condenser of 325 sq ft of tin foil with oil silk (100 sq ft permanent, buttons add 100, 75 and 50 sq ft); combined automatic and hand break (automatic break run by a one-cell battery); two coil halves usable apart or joined for 'quantity'. Dimensions (page image p.321): total height 18 1/2 in, base length 40 in, base height 5 in, base width 13 in, each secondary bobbin section 13 in long, bobbin external diameter 9 in (the width digits '13' and '18' differ little in print; the text layer and digest give 18, the page image reads 13). Packed weight (355 lb in three boxes) are given. Battery, made to Morton's direction by Chester Brothers of New York: three glass jars (10 x 12 in), each with five carbon and five zinc plates (8 x 10 in) lowered by windlass into bichromate and sulphuric acid solution; 3 in immersion gives full power when fresh. Morton reports it convenient in lecture courses in Baltimore and Washington; sparks of 21 in come freely and more might be reached, but he will not risk puncturing the insulating bell jars before his lectures end; Ritchie warrants it safe at 21 in. Observations: with a Leyden jar of 1 1/3 sq ft surface in circuit, sparks of 2 3/4 in (2 3/8 not fully excluded at 500 dpi); with one of Morton's secondary condensers (20 coated panes; Journal Vol. LIII p.256, not in this volume) 14 in sparks, 'of the intense whiteness and loud report of the Leyden jar discharge'; sparks pierce glass blocks 3 in thick, which seem to match 21 in of air (several air sparks pass between punctures, and a spark leaves its path a worse conductor so successive sparks take different routes); with an 8-pane secondary condenser the luminosity of a Gassiot cascade greatly exceeds that from any other coil, even Ritchie's 15-inch coils; coupled for quantity the spark falls to 12 in and the 'auriola' (glow round the discharge) increases, and with poles 4 in apart it can be blown into a flame-like surface extending 3 in; with four half-gallon Leyden jars the sparks are 'deafening' and light a 4 ft zoetrope disc so its figures are distinct at 60 ft. Wahl promises a later account of experiments; none appears in this volume's digests. Wahl is co-editor of the journal and is describing an instrument owned by the other editor. CORRECTION (2026-10-08, QE and arbiter): the earlier version of this entry, built from OCR, said 443 miles, 443 lb, 825 sq ft, 0.1635 in and a 14 sq ft jar with 2 in sparks, and read the contrast with App's coil as 'more wire, more reliable'. Those were OCR misreads. A 443-mile secondary of 0.007 in copper would weigh about 350 lb [computed], more than the whole 250 lb coil. Wahl's point is the reverse: 44 1/3 miles for 21 in, against App's 150 miles for 29 in. Other numbers re-read from the images: battery jars 10 in diameter by 12 in high, plates 8 x 10 in, five carbon and five zinc per jar, 3 in immersion; condenser 325 sq ft = 100 permanent + buttons of 100, 75 and 50; insulation tested 50 per cent above a 21 in spark.

Key claims

• Ritchie's coil for Morton is the most powerful induction coil then in existence, giving 21 inch sparks from three bichromate cells (about 44 1/3 miles of secondary wire, 250 lb total).
• A larger London coil (App, for Pepper; 150 miles of wire, about a ton) gave 29 inch sparks with about sixty cells but failed and was taken apart, whereas Ritchie's coil, with about a third of the wire, kept working for months.
• With a 1 1/3 sq ft Leyden jar in circuit the 21 inch coil gives sparks of about 2 3/4 inches; with Morton's 20-pane secondary condenser it gives 14 inch white, loud sparks.
• A spark of this coil punches a 3 inch glass block, whose resistance is about equal to 21 inches of air.
• Coupling the two coil halves for quantity shortens the spark to 12 inches and increases the quantity, shown by the sound and the 'auriola'.
• With four half-gallon Leyden jars the sparks are bright enough to show a 4 ft zoetrope disc distinctly at 60 ft.

Relevance: Gives the specification and performance of the Morton coil (the 'Morton' of the project name, with Wahl as the author; the folder name 'Morton-Wall' is read here as Morton-Wahl, an assumption) and the closest published precedent for Houston's observation that a Leyden jar or large capacity across the discharge makes the spark shorter, thicker, whiter and louder, and that quantity coupling shortens the spark. It also supplies the battery, which Houston omits.

Mainstream conflict: None. Standard mid-nineteenth-century induction-coil work. The spark-in-glass remark and the claim of 'most powerful now existing' are the author's statements, not independently checked here. Wahl and Morton are both editors of the journal and Morton owns the instrument described, so this is a description by an interested party (co-editor writing about his colleague's instrument), which says nothing against it but should be noted.

Short items in the same volume that show what the editors worked on. PDF p.362-363: Gassiot's electric star (Geissler tubes on rotating arms lit by induction-coil sparks); Morton's modification ties the tubes onto a cut card of any shape on a rotating vertical apparatus, with wires from the tube ends to a screw button and a pin on a vulcanite rod, and from an insulated stand to one pole of the coil. PDF p.449-451: Morton's 'vertical lantern' (condenser of three lenses, 45 degree mirror, third horizontal lens, objective) projects horizontal objects, such as waves in a tank, cohesion figures and magnetic spectra, onto a vertical screen; exhibited at a Franklin Institute meeting. PDF p.256-257: an editorial 'Magnetic Engines - their possible duty' computes ideal work from burning a pound of coal (7900 x 1390 = 10,981,000 ft-lb, about 332 hp for one pound a minute; the OCR prints '1890') against a good engine and boiler at 1 hp per 5 lb of coal per hour, 'say 4 per cent' of the ideal (the fraction is garbled in OCR), and zinc at 1301 x 1390 = 1,808,390 ft-lb per pound, and concludes that zinc would be about five times as effective as coal weight for weight, so a perfect battery and electric engine would compete only if zinc cost less than five times coal, and that 24 hp for 10 hours would need 27.4 lb of zinc 'with reference to some statements that have been published'. PDF p.266-267 (journal pp.159-160): the editors say the Rev. H. Highton (Chemical News) 'attacks ... the conservation of force' and maintains 'the possibility of ... perpetual motion'. Highton's argument as the editors state it: double both the cross-section and the length of the electromagnet wire so the circuit resistance stays the same; the current and zinc consumption stay the same, yet the lifting power doubles. The editors answer that power needs motion, so the magnet must be charged and discharged, and charging a double length of wire takes twice the time and twice the zinc; Highton replied that the current is so rapid the difference is 'inappreciable', which the editors reject ('two millionths of a second are as much twice one millionth as two centuries are twice one'). PDF p.448-449 (journal pp.299-300): the editors tie Highton's views to the reported performances of a galvanic engine at Newark, N.J., which they expect 'will reveal the true origin of its force'; the claim is that a sheet of tinfoil between successive layers of insulated wire on an electromagnet greatly increases its power. They cite Prof. Mayer (vol. LX p.410): inductive action of a wire on itself or of adjoining turns has no effect on magnetization; they note Mayer used copper disks between spirals, not cylinders between layers, so they repeated the experiment 'in this form, using the form of apparatus described by Prof. M. for comparison of strength in the magnetized cores', and 'when tinfoil was introduced exactly in the manner described by those claiming advantage from its use, no improvement whatever could be observed. H. M.' (Henry Morton; no numbers given, one test, the Newark inventors' side is not in the folder). PDF p.433 (journal p.288): S. P. Sharples (Silliman's Journal) found that a cell with nitric acid saturated with potassium bichromate (plus one-third volume sulphuric acid) has 'the same electro-motive force as an ordinary Bunsen; an internal resistance but fifty per cent. higher is sensibly constant for twelve hours and gives no fumes'; context for Morton's bichromate battery, whose EMF and resistance Wahl does not give. PDF p.431-432 notes Morton showing wave and cohesion figures in his new vertical lantern.

Key claims

• A card carrying Geissler tubes, rotated and lit by induction-coil sparks, makes a cheap version of Gassiot's electric star.
• Morton's vertical lantern projects horizontal objects (waves, cohesion figures, magnetic spectra) onto a vertical screen with a bright, undistorted field.
• A perfect battery and electric engine would need 27.4 lb of zinc for 24 hp for 10 hours; real steam engines use about 4 per cent of the ideal energy of coal.
• Highton's claim (doubling wire cross-section and length at fixed resistance doubles lifting power at the same zinc use) is a perpetual-motion claim, answered by the doubled charging time and zinc.
• Tinfoil between layers of insulated wire on an electromagnet gives no improvement when tested with Mayer's comparison apparatus (test reported by 'H. M.', PDF p.449; no figures given).

Relevance: Context for the editors' practice with coils and with claims of over-unity galvanic engines: the same editors who published Houston's note and Wahl's description rejected the Highton claim on an energy argument and tested the tinfoil claim. Peripheral to Houston's coil connection.

Mainstream conflict: None. The editors' own position is mainstream; the Highton and Newark engine claims they report are the ones that conflict with energy conservation, and are reported here as the editors' characterization of those claims, as their authors' side is not in the folder.

Kohlrausch (Reports of the Royal Academy of Gottingen, 23 Nov 1870) reviews absolute-resistance methods (Weber's two methods, earth inductor, the British Association rotating-coil method) and finds 1 B.A. unit = 1.0184 earth quadrant per second, in agreement with Jenkin; an attempt to measure Weber's electrochemical equivalent of water failed because a brass screw disturbed the readings. Mayer describes fixing iron-filing magnetic spectra in shellac for measurement, photography and lantern slides over 12 ft across, and a model of the earth's magnetic action. Chapin (Superintendent of the Fire Alarm Telegraph, New York, letter of 11 Aug 1870) compares a nitro-chromic battery fluid with the Electropoion battery on a 38 mile resistance galvanometer: after 20 hours the new battery read 30 and 15 degrees, the Electropoion 23 degrees and 'dead'. None of these items mentions the induction coil or Houston.

Key claims

• 1 B.A. unit of resistance equals 1.0184 earth quadrant per second (Kohlrausch's reduction of the B.A. determination).
• Iron-filing magnetic spectra can be fixed in a shellac film on glass and projected.
• A nitro-chromic battery fluid outlasts the Electropoion fluid in a 20 hour trial on a fire-alarm circuit (Chapin; Chapin has a stake as the battery's describer).

Relevance: Background on electrical practice in 1871 (units, batteries, field lines). Peripheral to the project's central claims.

Mainstream conflict: None.

The 623-page Google Books scan is the whole half-year volume, not just the Houston note. Besides the items above it contains the title and masthead pages (editors Morton and Wahl; the digests record 'forty-third year' on most mastheads and 'forty-sixth year' on p.604), the volume index (p.30 lists 'Induction Coil, On a Large, Wm. H. Wahl'), and advertisements for instrument makers (Queen & Co. and Francis & Milligan, Philadelphia, selling Ruhmkorff coils, Geissler tubes, Holtz electrical machines). The articles are on engineering and science: Thurston on British iron manufacture, ship magnetism and compass deviation, Nicaragua and Suez canals, Cornish and other pumping engines, belting, woodworking machines, Tilghman's sand-blast cutting, the 1870 solar eclipse (corona polarization, spectroscopy, Young, Pickering, Langley, Newcomb), Gould's lectures on the Sun, Ricour on dispersion of light, Leeds on geology and Pennsylvania rocks, Stimpson on carbon dioxide in illuminating gas, hydraulic mortar (Michaelis, Ott), chloral hydrate, crystallography (Wahl), pulverized fuel, petroleum refining, Franklin Institute proceedings, and the 1870 census. None of the remaining items bears on the induction coil, as far as the digests show.

Key claims

• Henry Morton and W. H. Wahl were the editors of the Journal of the Franklin Institute in 1871, and Wahl was Secretary of the Franklin Institute.
• Dealers in Philadelphia in 1871 advertised Ruhmkorff (induction) coils, Geissler tubes and Holtz electrical machines for sale.

Relevance: Context and provenance only: it establishes the editorial relationship between Morton and Wahl, the place and date of the Houston and Wahl articles, and the availability of coils in Philadelphia. The index and contents pages are the way to locate the two relevant articles.

Mainstream conflict: none