The following article from The Western Field magazine dates from August, 1904 gives a nice bit of history on the Kewell-Stewart spoon. The Kewell-Stewart spoon was patented in 1903 and was a staple for many decades.
A Famous Spoon
The Kewell's Stewart spoon -- one of the many indispensable fishing requisites carried in stock by the Charles H. Kewell Co., 1582 Market Street, San Francisco, is among the acknowledged leaders for striped bass and salmon fishing in Pacific waters. The appended illustration shows a Christmas (1903) catch of striped bass made by James M. Thompson on a No. 6 Stewart brass spoon, the eleven fish weighing 112 pounds, the largest scaling sixteen pounds. For trout, black and striped bass, steelheads, salmon and yellow tails it has proven a most successful lure, most particularly so for black bass in the Sierra lakes around Cisco, and for trout in the Truckee, Lake Tahoe, etc., and is well and favorably known from Puget Sound to Monterey as a salmon spoon, especially at Capitola, and at Eureka, Ferndale and Fortuna in Humboldt county, being used extensively at the mouth of the Eel river, taking large numbers of the "silver sides," etc.
We have it endorsed by a Chicago angler as a good lure for the lakes of Northern Wisconsin. Try one in any water of the world, and for any fish that will take a spoon of fish, and we will guarantee success. It has also taken many fish that usually can be taken only on bait--rockcod, cod, etc., and is said to possess a most distinct advantage over any spoon, spinner or artificial bait in existence. Possessing as it does more attracting power, about one-half the regular speed is all that is necessary. Although a high-speed is in no way detrimental, it merely works the faster and does not lose in the least its deadly alluring qualities.
The Kewell Co., manufacturing here in San Francisco, is at the services of anglers wishing to carry out their own ideas of flies. They have one of the largest stocks in the United States of materials for fly-making, leader-tying, etc., and have an unending stock of trout flies for you to select from. In addition, they carry all kinds of sporting goods and it will repay any sportsman to carefully examine their big assortment.
-- Dr. Todd