In re Cushman

6 F. Cas. 1066, 1 MacA. Pat. Cas. 569
District of Columbia Court of Appeals·Decided January 15, 1858·Published

Opinion

Morsell, J.

The claim as set forth in the amended specification is in these words : ‘ ‘ Having thus described -my invention, what I claim as new, and desire to secure by letters-patent, is surrounding that part of the lightning-rod which .is embedded in the earth with a galvanic-battery, in the manner and for the purposes set forth.” The nature of the invention is stated thus: “To facilitate the discharge of the electricity from the conductor to the earth is the object of my present invention, and it consists in surrounding that part of the lightning-rod embedded in the earth with plates of dissimilar metals, arranged in such manner as to constitute an open galvanic-battery. Electro-motive power will divide the electricity on the metallic plates, and as they are uninsulated they will act as a condenser of the electricity that is opposite to that of the air. Should there be a high electrical tension of the air, by this means the electrical fluid conducted through the rod is more readily discharged by uniting with the opposite electricity as it accumulates on the surface of the plates. When the discharge flows from the earth to the air, then the rod conducts from the plates such electricity as is opposite to that of the air.”

On the 3d of June, 1857, the Commissioner decided, refusing to grant the patent for reasons filed. The reasons alluded to appear to be contained in a report made by Examiner Baldwin, directed [570] to the Commissioner, in these words: "In the revision of the application of S. D. Cushman for a patent for alleged improvements in lightning-rods, I have the honor to report that the invention consisted in surrounding that part of the lightning-rod embedded in the earth with plates of dissimilar metals, to constitute an open galvanic-battery for the purpose of facilitating the discharge from the lightning-rod to the earth. The claim was, surrounding that part of the lightning-rod which is embedded in the earth with a galvanic-battery, in the manner and for the purposes described. Practical science has long since determined that to guard buildings against the destructive effects of lightning, it is necessary to provide a continuous line of conduction beyond the point of danger through which the electrical discharge may be transmitted, and it is well known that the building is rendered secure in proportion to the power of the conductor to transmit the electrical current. In Harris on Thunder Storms numerous examples are given to increase the security to buildings by extending the surface of the rod at its termination, and even directions are given to connect it there with conducting channels. For example, at page 97 it is said: ‘ It (the rod) should terminate under ground’ in two or more branches passing out in any convenient direction, ‘and if convenience permit, these branches should be connected with springs óf water or drain or some other conducting channel. ’ At page 105, same book, a clear view is given of the effect of the extension of surface in the power of conduction in the rod. At page 125 a drawing shows the forked termination of the rod; and at page 127 the description of the rod on the (Nelson monument mentions its termination connected with three pointed branches under the surface of the ground, while at page 134 is noticed the views of M. Le Roy in 1790, who proposed to protect the ship from the effects of lightning by terminating her conductors on the copper on her bottom. The modern experience with iron ships also shows that their large mass of conducting surface gives them almost a perfect immunity from the effects of lightning. In my opinion the application was properly rejected, for the use of plates of metal in which to terminate the rod for augmenting its security was not the invention of the applicant, and making this termination in plates of different metals could at most have but effected an infinitesimal action in the [571] power of conduction, and even this the Office cannot readily perceive any precise mode of verifying by experiment, and can therefore only receive it as a possibility ; but not even then can I regard it as presenting a doubt, of which the applicant should be allowed the benefit. I am, for these reasons, of opinion that the patent should be refused. ’ ’

This report and opinion was approved by the Commissioner on the 1st of June, 1857. From which decision said Cushman appealed, as before said, and filed his reasons of appeal, which are: First. Because the Office has failed to give references to show that the devices employed by the applicant were old or well known. Secondly. Because the Office has not shown that the invention is useless. Thirdly. Because the Office has failed to show that it is prejudicial to the morals of the community. Fourthly. Because the Commissioner had no right to reject the case on the ground that he could not perceive any precise mode of verifying by experiment the invention; and lastly, because wherever there is a doubt the applicant should receive the benefit of it.

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In re Cushman, 6 F. Cas. 1066, 1 MacA. Pat. Cas. 569 (D.C. 1858).

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