Walter I. Pennock's 1909 US Patent 911,260: A Balloon-Borne Collector for Atmospheric Electricity

US patent 911,260, "Apparatus for collecting atmospheric electricity", was filed by Walter I. Pennock on 26 June 1907 and granted on 2 February 1909. Pennock held it as an individual, with no company named as assignee, and it has long since expired. The patent proposes lifting a wire collector on a tethered balloon into what it calls the electrically laden upper strata of the air, and bringing the charge down a copper cable to be stored or used on the ground.

The document matters to this dossier mainly for its date. It was filed some sixteen years before Jules Guillot's first French patent of April 1923. The patent sets out a design and a rationale for it, and reports no measurements.

What problem does the patent say it solves?

Pennock's starting premise is that the upper atmosphere holds an electromotive force worth bringing to the ground for commercial use. Why does that energy not simply reach us? The patent's answer rests on two analogies. Rarefied air, it argues, conducts well, as a vacuum tube shows. Dense air insulates well, as shown by the electrodes of a static machine and by how little current leaks into the air from telegraph and trolley wires. Since the air thins with height, the patent pictures a conductive upper layer sitting above an insulating lower one, and concludes that the dense lower air blocks the current from reaching the ground.

The remedy follows directly: carry a collector up into the conductive layer and give the charge a metal path down through the insulating layer. The argument is built from these analogies. The patent cites no readings of atmospheric potential or conductivity, and names no altitude for the electrical layer it wants to reach.

What actually catches the charge?

The collecting element is a pair of spheres (6 and 6') formed from spiralled wire, held aloft on a wooden bar (4) whose two ends (7) are sharpened to points. The patent wants these spheres made of a conductor that stays bright in damp air, and so favours materials that resist moisture and tarnish. Platinum or gold would serve, whether as solid wire or as a plating over copper, and so would plain copper wire kept polished. Its drawing shows one sphere of plain wire and one of barbed wire, and it prefers the barbed kind, on the grounds that each barb adds another point where charge from the surrounding air can pass into the wire.

What carries the charge down, and where does it go?

The inner turns of both spheres are joined to one conductor (9), preferably a heavy copper wire, which hangs down to the ground. In the illustrated version it ends at one pole of a storage battery (10), whose terminals (15) can then run other equipment; a switch (16) optionally ties one battery pole to earth. The patent treats the battery only as an example. It says "accumulator" should be read as any useful device driven by the current arriving down the wire.

How is the balloon kept up and kept insulated?

Two practical worries take up much of the description. The first is weight: the patent concedes that heavy anchoring cables (12) could stop the main balloon (3) from climbing into the electrical layer, so it allows extra balloons (11) along each cable to bear some of that load. The second is leakage. If the tethers conducted, charge would run down them rather than down the copper wire, so the cables hang from a ring (13) under the main balloon via insulating rings (14), with optional further insulators along the cable runs and near the ground. Fixing the cable anchors (17) symmetrically, or in any arrangement other than a straight line, is said to hold the balloon in a roughly fixed position.

What does the document not establish?

The patent gives no altitude, voltage, current, power, energy or duration, and it does not establish that a balloon was ever flown or that any current was collected. Its physical case rests on analogies to laboratory devices, not on observations of the atmosphere. The grant itself is not evidence that the design worked.

The Google Patents record lists several dozen later patents that cite this one. They include a 1965 "Ionospheric battery" (Leslie G. Smith), a 1966 "Balloon carried antenna" (Alfredo Bartolini), Heinz W. Kasemir's "Weather control by artificial means" (1966), and a run of "Energy collection" patents from Clint McCowen and Ion Power Group from 2006 onward. A citation records that an examiner or applicant judged the earlier patent relevant prior art. It says nothing about whether the 1909 device performed.

How does it fit the rest of the dossier?

Robert A. Nelson's survey names Pennock as an early inventor of aerial collectors, citing US911260 (1909) and a later patent, US1014719 (1912), and claims no output for either. The 1909 patent bears that out: it offers no figures to report. Its date also shows that balloon-lifted collection was patented in the United States by 1909, before Plauson's 1920 book and the Science & Invention accounts of his balloons that Nelson quotes. Andry-Bourgeois also mentions German captive-balloon trials, without dating them.

Guillot's arrangement, as reported in 1923, differs in its approach. It is a fixed double aerial on a mast of about 15 to 20 metres, with a zenith-pointing fan and a south-facing point, plus regulators and an "aspirator" said to draw charge in. Pennock instead tries to reach a supposed conductive layer by sheer height and relies on points and a wire alone. The two documents also differ in what they report. The 1923 article describes a demonstration in which Guillot's collector lit ten 50-candle lamps, in experiments said to have been supervised by experienced engineers, but it states no power, voltage or current. Pennock's patent reports no result of any kind.

Further reading

• Guillot and Eclator for the French inventor and his apparatus.
• Power from the Air: Robert A. Nelson's Survey of Atmospheric Electricity Collectors, from Palenscar to Guillot and Plauson for the wider list of atmospheric-power patents.
• The Practical Use of Atmospheric Electricity: Andry-Bourgeois's June 1923 Account of Jules Guillot's Double-Antenna Collector in La Science et la Vie for the contemporary description of Guillot's mast collector.