[EDISON, Thomas Alva (1847-1931), association]. CLARKE, Charles Lorenzo (1853-1941). Archive for the Report, “Economy Test of the Edison Electric Light”. [Menlo Park, N. J., Schenectady, N. Y., 1881-1932]. An impressive archive of material written and later annotated by Clarke, Edison’s Chief Engineer for the Edison Electric Light Company. Clarke has signed several items herein. Most of the archive is housed in a plain folder with brad clips with the typed legend “Economy Test of the Edison Electric Light by Chas. L. Clarke / Menlo Park, N. J. Jan. 1881”. Front of folder is signed by Clarke in blue ink at the bottom right. The contents of the folder are as follows: Cover page on Clarke’s stationery (“Chas. L. Clarke Electrical and Mechanical Engineer 120 Broadway, New York”) with manuscript date of July 10, 1905. 4to. Approximately 259 x 215 mm. Folded in center to fit into folder, minor occasional soiling. In Clarke’s hand: “The following is a copy of a report (made at the time the report was completed), that I made to the Edison Electric Light Company, of an economy test on the Edison Electric Light, which was conducted at Menlo Park, New Jersey, under my supervision. At the time the test was made, I was one of Mr. Edison’s laboratory assistants. Chas. L. Clarke.” -- Nineteen-page typescript report/article, “Economy Test of the Edison Electric Light”. 4to leaves, rectos only, on white onionskin paper. Approximately 257 x 207 mm. Folded in center to fit into folder (a bit toned, soiled, edgeworn). With manuscript ink numbers, symbols, notes throughout. “Before the trial of the One Hundred horse-power dynamo-electric machine which is now approaching completion, and which is to be driven by a Porter-Allen engine, acting directly upon the armature shaft, Mr. Edison desired to have a thorough text made to satisfy himself as to the economy of the lights resulting from the employment of the present small dynamos, large slow-speed engine, and boilers which are acknowledged by mechanical engineers as being among those of the most modern and economical types. The results have proven so satisfactory that Mr. Edison desires to place the information gained before the Engineering world.” -- “Diagram of a part of the Log kept during the Economy Test of the Edison Electric Light. Jan. 29, 1881”. Oblong folio. Original manuscript diagram on grid paper of Boiler Pressure, Indicated Power, Temperature of Feed-Water, Heat in Steam by Calorimeter, Line of Heat in Dry Steam. Approximately 204 x 432 mm. Four vertical creases to fit into folder (a bit toned, pin-holes at corners). With the later pencil note by Clarke: “This chart was made by Julius L. Hornig, Edison’s mechanical engineer and designer at Menlo Park New Jersey. Chas. L. Clarke Nov. 26, 1932.” -- Three-pages of two manuscript diagrams each of steam indicators, all mounted on three leaves of Clarke’s stationery (two diagrams per leaf). 4to stationery leaves approximately 259 x 215 mm. Diagrams approximately 90 x 179 mm. Stationery leaves folded at center to fit into folder, some occasional soling to leaves and diagrams, occasional chipping, short tears to diagrams. The following caption on the first leaf in Clarke’s hand: “July 10, 1905. The following six steam-indicator diagrams are some of the original diagrams that were taken during the economy test at Menlo Park. Chas. L. Clarke.” -- A leaf of ruled paper with the following manuscript caption: “Economy Test of the Edison Electric Light Menlo Park-Jan. 29, 1881”. Above this caption is Clarke’s inkstamp. 8vo. Approximately 242 x 202 mm. Folded at center to fit into folder (toned, some soiling, wear). This may have been an early sheet folded around the previous diagrams to keep them separated from other material. – Fifteen-page typescript, “Economy Test of the Edison Electric Light”. New York: Feb. 17, 1904. 4tos. Plain white onionskin paper, rectos only. Approximately 279 x 202 mm. Toned, some light wrinkling, rubbing. With the following pencil notes on the first page by Clarke: “This is an editorial revision of my original report of Feb. 7, 1881. It has been too much changed from the original. Who did it I do not know. I added the foot-notes, but apparently without comparing this text with the original closely at least, to see if they were alike. This I have recently done, Chas. L. Clarke. 1/14/1933”. “The foot-notes were added by me to the editorial revision in 1904.” “Should be Saturday and Sunday, Jany. 29-30, 1881. Chas L. Clarke. Dec. 5, 1932” (with an arrow pointing to a portion of the typed text). -- CLARKE, Charles Lorenzo. “Economy Test of the Edison Electric Light / 1881”. Schenectady: General Electric Company, 1904. 4to. [12] pp. Approximately 265 x 190 mm. Some rubbing, soiling. This is the revised version which Clarke mentions above. On the front self-wrapper (p. [1]) is the following note by Clarke in ink: “Printed at the press of the General Electric Company, at Schenectady, N. Y., 1904”. Another copy of this report is laid-in (no markings by Clarke).

Laid-in are the following items: CLARKE, Charles Lorenzo. Carbon Copy of an Autograph Letter Signed to His Friend and “Edison Pioneer,” Francis Jehl (1860-1941), Schenectady, N. Y., Jany. 9, 1933. 2 4to pages on two leaves. Addressed: “Dear Francis”. Carbon copy is on thin paper. Approximately 279 x 215 mm. A bit toned, folded at center, pinned at upper left corner. “Your letter of the 2nd is here, wherein is a photostat copy of pages from your Menlo Park, N. J. diary of 1881 [this large photostat page of this diary is included in this archive - see below], covering the dates: Thursday to Sunday, Jany. 27th to 30th, inclusive, Which indicate that the famous Edison Light Economy Test was made on the night Saturday and Sunday, Jany. 29-30, 1881, and not, as stated by me in the foot-note on page 166 of “Edisonia,” of 1904, on Friday and Saturday night, Jany. 28-29.” Clarke goes onto good-naturedly defend his mistake in the date he put into the footnote. -- JEHL, Francis (1860-1941). Typed Letter Signed from Laboratory Assistant and “Edison Pioneer” Jehl to Clarke. Dearborn, Mich: January 5 1933. 3 8vo pages on 3 leaves. Addressed to Chas. L. Clarke “My dear Clarke:-” On personal stationery. Approximately 178 x 151 mm. Horizontal crease near bottom, minor rubbing. “Personal + Confidential” in ink at top left of the first page. With pencil notes throughout apparently by Clarke; signed by Jehl on the final page. In this letter, Jehl asks Clarke to edit down the Economy Test report so he can use it to sell Edison Electric Lights in Europe (which was Jehl’s task at the time). He also describes the work done on a dynamo he was working on with Henry Ford (“H. F.” in the letter), which he refers to as “Jumbo.” This letter is stapled at the upper left corner to a carbon copy of the two-page autograph letter signed response by Clarke (Schenectady, N. Y., Jany. 9, 1933). 2 4to pages on two leaves. Addressed: “Dear Francis”. Carbon copy is on thin paper. Approximately 279 x 215 mm. A bit toned, folded at center. “Yes, the old Edison dynamos took the cake for ‘economy and life’, and do today. But competition has come into cut these down. One of the G. E. engineers told me, when I was over seeing the building of replicas of the 1879 and 1880 dynamos: ‘If we couldn’t get six times the output for the same iron and copper, we’d lose our job.’” Clarke became president of the Edison Pioneers in 1925 (see below). -- Large Photostat Copy of Francis Jehl’s Diary as Mentioned Above. [Ca. 1933]. Folio. Approximately 362 x 486 mm. One horizontal and one vertical creases, a bit toned, rubbed. Photostat copy of the January 27-30, 1881 entries of Jehl’s diary. With the following pencil note by Clarke near the top right: “Photostat of some pages from a diary Kept by Francis Jehl, at Edison’s Laboratory, Menlo Park, New Jersey. The entries of January 29-30, 1881 relate to the famous Economy Test of the Edison Electric Light at Menlo Park, 1881, published later in Edisonia, 1904, wherein a foot-note by me, page 166, the day of the test is erroneously stated to be January 28-29, 1881. Chas. L. Clarke - Schenectady, N. Y. Dec. 5, 1932”. -- CLARKE, Charles Lorenzo. Manuscript Footnotes Written by Clarke. [Ca. 1910s]. One 8vo page on folded 4to leaf of plain cream-colored paper. Page approximately 217 x 139 mm; leaf is approximately 217 x 278 mm. Minor occasional soiling. Unsigned. Some entries are: “Kent’s Mech. Engrs. Pocket Book, 1916- ‘horse-power’”, “Sprague - Electricity - 1875 ‘Electromotive force’”, “Higgo - The Elec. Light, 1879 ‘horse Power’ ‘electro motive force’” and more. -- [CLARKE, Charles Lorenzo]. Page 5 of the March 20, 1925 issue of Schenectady G. E. Works News. [General Electric, 1925]. Excised page from this company newsletter, with the article, “Chas. L. Clarke Elected President of the Edison Pioneers” with accompanying article and portrait of Clarke. Approximately 265 x 200 mm. A bit toned, left margin chipped from being removed from the newsletter. This group held in Clarke’s envelope from “Mechanical Engineering” magazine. With “Economy Test Edison Electric Light 1881 by CLC” written on the front (some wear, soiling). -- An incredible archive of materials related to one of the important steps of selling industry, scientists, and the public on the efficiency and effectiveness of the Edison Electric light bulb (though he invented the earliest versions of the bulb in 1879, he spent next few years trying to get it widely accepted), and a detailed peek into the Edison Company, as seen by one of its top scientists and designers.