The following appeared in the Rock County Herald on August 11, 1916. BIG ANNUAL ROYALTY FOR PATENT RIGHTSL.A McDowell Disposes of His Patent Rights in M. C. D. Spark Plug to Sioux City Firm$12,000 ANNUALLY FOR LIFE OF PATENT PAIDPurchasers are Coleman-Johnson Company, who Plan Big Increase in Sale of The Plugs.Under the terms of a deal consummated Friday, L.A. McDowell, of this city, disposed of the exclusive rights to manufacture and sell the M. C. D. spark plug in the United States to the Coleman-Johnson Brokerage Co., of Sioux City. The terms of the sale provide that the minimum amount of royalty that Mr. McDowell is to receive is $12,000 a year for the period covered by the patents on the invention. Mr. McDowell invented the spark plugs about five years ago, and since placing them on the market shortly thereafter has enjoyed a large demand for them, but considerable difficulty has been encountered in securing their manufacture in large enough quantities. The Coleman-Johnson company is now negotiating with the Campbell Motor Co., of Minneapolis, for the manufacture of the device, and under the arrangement being made this company guarantees to furnish the spark plugs in sufficient quantity to meet all demands. The Coleman-Johnson company is already promoting the sale of the plugs on an extensive scale, and according to word received Tuesday had secured orders for 15,000 of them from retail dealers.Donations to the Rock County Historical Endowment Fund can be sent to the Rock County Historical Society, P.O. Box 741, Luverne, MN 56156.Mann welcomes correspondence sent to mannmade@iw.net.