Incandescent lamps of the past often carried names of inventors who had input into the specifics of the design. On the other hand, some individuals who made significant contributions to the processing of a lamp design might never have his or her name associated with the marketing of the product. The person of interest in this writeup is one whose name wasn't closely associated with the marketing activities. His name was Adolph Berrenberg and his contributions to lamp production were closely associated with vacuum pumps and the exhausting of lamp bulbs.
Adolph Berrenberg was born on 6 January 1853 in the village of Griemeringhausen, which in now part of Marienheide, Germany. He became a champion marksman with the rifle and in 1876 founded, with one of his brothers, Reinold, the present-day sportsclub known as "TUS Meinerzhagen." His father, Wilhelm, ran a small factory that was associated with agricultural machinery. Adolph emigrated to the Boston area of the United States in 1878. Upon arriving in the United States he worked as a machinist for a few years. On the 26th of July in the year 1879 he married Anna Maria Geishecker, who was the daughter of German immigrants.
An article about lamp vacua (The Vacuum in Lamp Bulbs), written by Berrenberg, appeared in The Electrical World as well as the English Mechanic and World of Science in 189211. The Electrical World write-up appears below.
The most widely known association of Berrenberg with a United States manufacturer of incandescent lamps is probably that with the Beacon Vacuum Pump and Electrical Company. It is believed that that company was formed about May of 1890 when the vacuum pump patents of Berrenberg and William Emery Nickerson were to be utilized in manufacture. Beacon began to manufacture incandescent lamps about a year later, in May of 1891. Unfortunately, after the formation of the General Electric Company in 1892, litigation was started against several lamp manufacturers for infringement of the basic Edison patent. This terminated production of the Beacon lamp until a non-infringing one could be placed on the market.
It should be noted that Berrenberg was affiliated with other inventors, such as William Emery Nickerson, Rudolf Langhans, and Edwin Dunbar Chaplin. Berrenberg-Nickerson patents are listed below. Langhans is noted for working on a silicon-carbon filament lamp, whereas Chaplin patented a vacuum pump (US 521,432 and GB189411377). One Berrenberg patent was co-invented with his brother, William.
Adolph Berrenberg was closely associated with several lamp manufacturing companies. Examples follow:
The Beacon Vacuum Pump and Electrical Company - Organized in May 1890 for the manufacture of the Berrenberg pumpA report was written by Professor W. E. Ayrton, after he did an evaluation of the Berrenberg-Chaplin Pump, and it was sent to the Langhans-Berrenberg-Chaplin Patents (Limited). An article appeared in The Electrician24 that gave a description of the pump. The conclusions drawn from that work are shown below.
Langhans-Berrenberg-Chaplin Patents, Limited - Registered 31 Dec 189522.
Berrenberg Electric Lamp Syndicate, Limited - Incorporated 11 Feb 1898.
Langhans-Berrenberg-Chaplin Patents, Limited - Dissolved 190030, 31.
Berrenberg'sche Elektricitäts-Werke, G.m.b.H. - Established 29 Jan 1904 with Richard Drecker. Renamed Radium-Elektricitäts-Gesellschaft m. b. H. on 17 Dec 190448.
Berrenberg Electric Lamp Syndicate, Limited - Dissolved 190435, 36.
Phoebus G.m.b.H., near Düsseldorf, Germany, 1907-1912.
Glühlampenfabrik Reisholz G.m.b.H., 1913.
Edward Schroeder Lamp Works, Jersey City, New Jersey (1914-1919).
Adolph Berrenberg wrote a letter to the editor of The Electrician26 after the results of Dr. Ayrton were published. That letter appears below.
|Item||Patent No.||Filing Date||Issue Date||Description||Assignor(s) to||Berrenberg Residence (at time of filing)|
|1.||US305,417||28 Jan 1884||23 Sep 1884||Shifting Pulley||------||Boston, MA||2.||US337,551||13 Jul 1885||9 Mar 1886||Rotary Engine (with William Berrenberg)||Positive Pump and Water Meter Co. (Kittery, ME)||Boston||3.||US369,092||4 May 1886||30 Aug 1887||Registering Apparatus||------||Boston||4.||US369,093||4 Dec 1886||30 Aug 1887||Piston-Packing||Louis Post||Boston||5.||CA 29516||------||23 Jul 1888||Counter or Recording Device||------||------||6.||US421,346||2 May 1888||11 Feb 1890||Vacuum-Pump||Jacob Heilborn and Anna M. Berrenberg||Somerville, MA||7.||US422,705||18 Oct 1889||4 Mar 1890||Switch (with Jacob Umbehend)||------||Somerville||8.||US447,256||20 Jun 1890||24 Feb 1891||Apparatus for Flashing and Exhausting Incandescent Electric Lamps (with Wm. E. Nickerson)||The Beacon Vacuum Pump and Electrical Co. (Portland, ME)||Somerville||9.||US447,273||10 May 1890||24 Feb 1891||Vacuum-Pump (with Wm. E. Nickerson)||Beacon||Somerville||10.||US447,274||10 May 1890||24 Feb 1891||Vacuum-Pump (with Wm. E. Nickerson)||Beacon||Somerville||11.||US447,275||2 Jun 1890||24 Feb 1891||Vacuum-Pump Connection||Beacon||Somerville||12.||US450,795||20 Jun 1890||21 Apr 1891||Air-Tension Gage (with Wm. E. Nickerson)||Beacon||Somerville||13.||US452,441||2 Jun 1890||19 May 1891||Vacuum-Pump (with Wm. E. Nickerson)||Beacon||Somerville||14.||US453,277||20 Jun 1890||2 Jun 1891||Vacuum-Pump (with Wm. E. Nickerson)||Beacon||Somerville||15.||CA 39206||------||24 Jun 1892||Apparatus for Exhausting Incandescent Lamps (with Wm. E. Nickerson)||Owner: Henry Sachs Kaliske||------||16.||CA 39997||------||24 Aug 1892||Vacuum Pump||------||------||17.||CA 43204||------||10 Jun 1893||Vacuum Pump (with Wm. E. Nickerson)||Owner: Henry Sachs Kaliske||------||18.||CH10305||9 May 1895||15 Nov 1895||Motorrad (with Wilhelm Krauss)||------||Boston||19.||GB189509922||20 May 1895||28 Dec 1895||Improvements in Wheel Motors for Cycles and other similar Vehicles (with Wilhelm Krauss)||------||Sommerville||20.||CH12512||6 Jul 1896||15 Jan 1897||Machine motrice perfectionnée destinée à la propulsion des voitures automobiles, telles que voitures de tramways, voitures routières, etc. (with John Howard)||------||Surrey||21.||CA 54619||14 Nov 1896||16 Jan 1897||Motor Engine (with John Howard)||------||------||22.||GB189607454||8 Apr 1896||16 Jan 1897||Improvements in the Construction of Motor Engines, and their Application in the Propulsion of Auto-cars or Road-carriages||------||Surrey (GB)||23.||CH18005||21 Oct 1898||30 Sep 1899||Doppeltwirkende Vakuumpumpe||------||London (GB)||24.||CH18073||21 Oct 1898||15 Oct 1899||Mehrkolbige Vakuumpumpe mit Vorrichtung zur Aufhaltung der Kolben in ihren Grenzlagen||------||London||25.||GB190000378||8 Jan 1900||17 Nov 1900||Improvements in the Manufacture of Glass Articles, Shades, Reflectors and the like, and in Apparatus therefor (with Otto Hellstern)||Berrenberg Electric Lamp Syndicate Limited||Southfields (GB)||26.||DE115426||14 Oct 1898||5 Dec 1900||Doppeltwirkende Vacuumpumpe||------||London||27.||DE121754||14 Oct 1898||1 Jul 1901||Vakuumpumpe||------||London||28.||US747,190||1 Aug 1895||15 Dec 1903||Motor-Wheel for Bicycles or Other Vehicles (with Wilhelm Krauss)||------||Boston|
Patents were also issued to Berrenberg and Nickerson in Mexico49-52. European patents other than those listed above probably exist. Provisional patents were also issued in England in 1891 (3357 and 3364). It should be noted that patent listings on esp@cenet are not complete for early years.
One of the most complete collections of early incandescent lamps was assembled by William J. Hammer, an employee of Thomas A. Edison. Hammer collected samples of Edison lamps as they were developed as well as lamps from other inventors located world wide. In one of his publications he listed a Berrenberg lamp as being in the collection37.
The Hammer Collection of Incandescent Lamps is presently housed at the Henry Ford Museum in Dearborn, Michigan56. The writer has a copy of the inventory of that collection (obtained from the Henry Ford Museum & Greenfield Village Research Center) and each lamp has a card associated with it. Hammer wrote pertinent lamp information on the cards for each lamp. The text on Card No. 1903-865 reads: "English - Berrenberg - 1903. 220-volt 16-cp, anchored spiral, carbon paste clamps, English type porcelain base. Presented to me by Westinghouse Lamp Company, Bloomfield, N. J., April 23, 1913." Markings on the lamp are: "220-16 Berrenberg". When the date, 1903, is considered, the writer surmises that the lamp was manufactured by the Berrenberg Electric Lamp Syndicate, Limited.
In 1918 A. Berrenberg was located in New York City, working as a Consulting Engineer39. In a Directory of Engineers it was stated that he had erected lamp and wire plants in the United States, Canada, England, Sweden, Russia, Germany, Italy and France.
Below is information regarding some family members.
Adolph Berrenberg passed away in Jersey City, New Jersey on 7 Aug 1919.Reinold Berrenberg, Adolph's son, followed his father into the lamp business, working at one time as the advertising manager and then as the general sales manager of the Lux Manufacturing Company, an independent manufacturer of lamps38. Lux was located in Hoboken, New Jersey.
Adolph had six brothers; three, namely William, Albert and Reinold, were also granted U. S. Patents. The other three were Arnold, Alfred and John.
Adolph had two sisters: Florentine and Emma.
Anna Maria (Geishecker) Berrenberg, wife.
Reinold Berrenberg (1884-1931), son.
Anna Berrenberg, born 26 May 1885 in Boston, daughter53.
Bertha Rosa Angeline Berrenberg, born 27 Apr 1886 in Boston, daughter53.
Agnes Barbara Berrenberg, born 30 Sep 1890 in Boston, daughter53.
Rose Berrenberg, born 18 Aug 1891, daughter47.
The writer's interest in researching Adolph Berrenberg was initiated by a letter from Dr. Rüdiger Schneider Berrenberg of Agiokambos/Agias, Larissis, Thessalia, Greece. Significant information about his early relative was obtained in his several letters. A communication from Dr. Joy L. Berrenberg, Associate Professor of Psychology at the University of Colorado (Denver), great granddaughter of Adolph, was also of immense value for this writing. Thanks are hereby given these two relatives of Adolph Berrenberg. The picture of Berrenberg was scanned from Reference No. 40.
References and Bibliography
1) Silver Medal - Rotary Pumps, pg 147; Bronze Medal - Counter, pg 173, 16th Triennial Exhibition of the Massachusetts Charitable Mechanic Association, 1887. http://books.google.com/books?id=6BwaAAAAYAAJ&pg=RA2-PA206&lpg=RA2-PA206&dq=%22adolph+berrenberg%22+award&source=bl&ots=GdeMOfuZJK&sig=xXUlwCtrFKt1Z06OkTu5rOYKF-o&hl=en&ei=d4X8StfIJ4LWtgPdsZH3Bg&sa=X&oi=book_result&ct=result&resnum=2&ved=0CAwQ6AEwAQ#v=onepage&q=%22adolph%20berrenberg%22%20award&f=false
2) The Electrical Engineer, Vol 9, 16 Apr 1890, pg 251. http://books.google.com/books?id=BwUAAAAAMAAJ&pg=PA251&lpg=PA251&dq=berrenberg+air+pump&source=bl&ots=4AfmUIZZLa&sig=35MEQUObSD95naXB3UJKmH12GV8&hl=en&ei=eQELS4D1EdLDlAfEjLCFBA&sa=X&oi=book_result&ct=result&resnum=1&ved=0CAwQ6AEwAA#v=onepage&q=berrenberg%20air%20pump&f=false
3) "Berrenberg Air Pump," The Electrical Engineer, New Series, Vol 5, 2 May 1890, pp 341-342. http://books.google.com/books?id=yp8vAAAAYAAJ&pg=PA341&lpg=PA341&dq=berrenberg+air+pump&source=bl&ots=olqTZ4Pkb1&sig=xgU2PuwHdNBjylkqbYFmq7fLkgU&hl=en&ei=6wQLS_iZDM_HlAeCuIiFBA&sa=X&oi=book_result&ct=result&resnum=4&ved=0CBUQ6AEwAw#v=onepage&q=berrenberg%20air%20pump&f=false
4) The Electrical Engineer, Vol 9, 21 May 1890, pg 380. http://books.google.com/books?id=BwUAAAAAMAAJ&pg=PA380&lpg=PA380&dq=berrenberg+air+pump&source=bl&ots=4AfmUIZZLa&sig=35MEQUObSD95naXB3UJKmH12GV8&hl=en&ei=eQELS4D1EdLDlAfEjLCFBA&sa=X&oi=book_result&ct=result&resnum=1&ved=0CAwQ6AEwAA#v=onepage&q=berrenberg%20air%20pump&f=false
5) "Berrenberg Pump," The Electrical Engineer, Vol 5, 6 Jun 1890, pg 440. http://books.google.com/books?id=yp8vAAAAYAAJ&pg=PA440&lpg=PA440&dq=berrenberg+pump&source=bl&ots=olqTZ4OodY&sig=5bKWCTLvCCTnb0WQ5q9mERO7VK0&hl=en&ei=oQILS9WFMJHdlAeGk-yEBA&sa=X&oi=book_result&ct=result&resnum=7&ved=0CB8Q6AEwBg#v=onepage&q=berrenberg%20pump&f=false
6) "The Berrenberg Vacuum Pump," The Electrical Engineer, Vol 10, 26 Sep 1890, pp 256-257. http://books.google.com/books?id=0AgAAAAAMAAJ&pg=PA256&lpg=PA256&dq=%22the+berrenberg+vacuum+pump%22&source=bl&ots=BeBaaaL970&sig=bz5snDFtzhtYHYcAlwOCf-oYLuI&hl=en&ei=DU4LS6mmDtGzlAfNnP2ZBA&sa=X&oi=book_result&ct=result&resnum=2&ved=0CA4Q6AEwAQ#v=onepage&q=%22the%20berrenberg%20vacuum%20pump%22&f=false
7) "The Beacon Vacuum Pump for Exhausting Incandescent Lamps," The Electrical Engineer, Vol 11, 4 Mar 1891, pp 266-268. http://books.google.com/books?id=ESQAAAAAMAAJ&pg=PA266&lpg=PA266&dq=beacon+vacuum+pump&source=bl&ots=k7EQvvCKQq&sig=EsGvDCHY5SNH6KqCW2XUyN81c-o&hl=en&ei=mSYLS4aXFIGesgOVxZVE&sa=X&oi=book_result&ct=result&resnum=9&ved=0CCUQ6AEwCA#v=onepage&q=beacon%20vacuum%20pump&f=false
8) "The Packard Vacuum Pump for Exhausting Incandescent Lamps," The Electrical Engineer, Vol 11, 6 May 1891, pg 527. http://books.google.com/books?id=ESQAAAAAMAAJ&pg=PA527&lpg=PA527&dq=the+packard+vacuum+pump+for+exhausting&source=bl&ots=k7FKAtFDQj&sig=LxuBW0Gn6emzuh-qo0I6sQysggM&hl=en&ei=jotPS96-FsyRlAfVhLWwCg&sa=X&oi=book_result&ct=result&resnum=1&ved=0CAsQ6AEwAA#v=onepage&q=the%20packard%20vacuum%20pump%20for%20exhausting&f=false
9) New England Trade Notes, Beacon Vacuum Pump and Electrical Company, The Electrical Engineer, Vol 12, 2 Sep 1891, pg 272. http://books.google.com/books?id=my4AAAAAMAAJ&pg=RA5-PT272&lpg=RA5-PT272&dq=new+england+trade+notes+beacon+vacuum&source=bl&ots=6o_JwmHzBX&sig=DXtAHmRAjY5ir4G2TFp_xv3084A&hl=en&ei=p1ULS-2_BoH0sgOhrqWkAw&sa=X&oi=book_result&ct=result&resnum=1&ved=0CAkQ6AEwAA#v=onepage&q=new%20england%20trade%20notes%20beacon%20vacuum&f=false
10) New England Notes, The Electrical Engineer, Vol 12, 30 Dec 1891, pg 720. http://books.google.com/books?id=my4AAAAAMAAJ&pg=RA5-PT720&lpg=RA5-PT720&dq=electrical+engineer+exhausting+larger+sizes+of+incandescent+lamps&source=bl&ots=6o_JxlEEA-&sig=uJiKNHL55REKGD6RW6dQmGVi4ok&hl=en&ei=bKsMS8jSMongtgO7oOSYAw&sa=X&oi=book_result&ct=result&resnum=4&ved=0CBEQ6AEwAw#v=onepage&q=electrical%20engineer%20exhausting%20larger%20sizes%20of%20incandescent%20lamps&f=false The image obtained online is difficult to read sometimes. The brief article is presented in the text.
11) Adolph Berrenberg, "The Vacuum in Lamp Bulbs," The Electrical World, Vol 19, 28 May 1892, pp 364-365. Also - English Mechanic and World of Science, Vol 55, 17 Jun 1892, pg 379. http://books.google.com/books?id=T4UAAAAAMAAJ&pg=PA379&lpg=PA379&dq=beacon+vacuum+pump+berrenberg&source=bl&ots=vEdhypFMfH&sig=dluSi7-Vk9DAjsVtr66-JtDmptU&hl=en&ei=oSz7SpDGHYaQlAeZuci6Aw&sa=X&oi=book_result&ct=result&resnum=2&ved=0CAsQ6AEwAQ#v=onepage&q=beacon%20vacuum%20pump%20berrenberg&f=false.
12) "The Beacon Incandescent Lamp," Western Electrician, Vol 10, 18 Jun 1892, pg 369.
13) J. W. Packard, "Exhausting Incandescent Lamps by Means of Mercury Pumps," The Electrical Engineer, Vol 14, 20 Jul 1892, pg 57.
14) Legal Notes - Incandescent Lamp Litigation in Boston, The Electrical Engineer, Vol 15, 18 Jan 1893, pg 70.
15) Correspondence - Our Boston Letter, Electrical Review, Vol 22, 4 Mar 1893, pg 35.
16) "Incandescent Light Litigation - Edison Electric Light Company vs. Beacon Vacuum Pump and Electrical Company," The Electrical Engineer, Vol 15, 15 Mar 1893, pg 274.
17) Science Notes. Berrenberg Vacuum Pump. Otago Witness, Issue 2058, 3 Aug 1893, pg 48. http://paperspast.natlib.govt.nz/cgi-bin/paperspast?a=d&d=OW18930803.2.201&e=-------10--1----0-all
18) "The 'New Beacon' Non-Infringing Incandescent Lamp," The Electrical Engineer, Vol 16, 23 Aug 1893, pp 169-171.
19) Correspondence - Our Boston Letter, Electrical Review, Vol 23, 26 Aug 1893, pg 7.
20) The Electrician, Vol 36, Nov 1895 - Apr 1896, pg 417.
21) "The Berrenberg Metallic Vacuum Pump," The Electrical Engineer, Vol 17, New Series, 10 Jan 1896, pp 37-39. http://books.google.com/books?id=-ZcvAAAAYAAJ&pg=PA37&lpg=PA37&dq=the+berrenberg+metallic+vacuum+pump&source=bl&ots=KLdUfkJXIf&sig=Sr9eYiZtmwc5F5s_aW02DzI1F6I&hl=en&ei=oI5PS5DuAoiOtAOA0-n2Bw&sa=X&oi=book_result&ct=result&resnum=4&ved=0CBYQ6AEwAw#v=onepage&q=the%20berrenberg%20metallic%20vacuum%20pump&f=false
22) "Langhans-Berrenberg-Chaplin Patents, Limited," The Electrical Engineer, Vol 17, New Series, 10 Jan 1896, pg 55. http://books.google.com/books?id=ObrmAAAAMAAJ&pg=PA55&dq=langhans+chaplin&cd=4#v=onepage&q=langhans%20chaplin&f=false
23) Berrenberg mechanical vacuum pump, The Electrician, Vol 36, No 13, 24 Jan 1896, pg 399.
24) "The Berrenberg-Chaplin Vacuum Pump," (Report by Prof. W. E. Ayrton, F.R.S., to the Langhans-Berrenberg-Chaplin Patents (Limited)), The Electrician, Vol 36, No 13, 24 Jan 1896, pp 417-420.
25) "The Berrenberg-Chaplin Vacuum Pump," The Electrical Engineer, Vol 17, New Series, 24 Jan 1896, pg 86. http://books.google.com/books?id=-ZcvAAAAYAAJ&pg=PA86&dq=the+berrenberg-chaplin+vacuum+pump&cd=1#v=onepage&q=the%20berrenberg-chaplin%20vacuum%20pump&f=false
26) Adolph Berrenberg, Correspondence, The Berrenberg Vacuum Pump - to the Editor of The Electrician, The Electrician, Vol 36, No 13, 31 Jan 1896, pp 453-454.
28) "Fahrräder mit Kraftbetrieb," pg 228. Dingler's Polytechnisches Journal, Vol 303, 1897, pp 225-232.
29) "Berrenberg Incandescent Lamp Factory," The Electrician, Vol 44, 3 Nov 1899, pp 35-38. http://books.google.com/books?id=ehMAAAAAMAAJ&pg=PA165&lpg=PA165&dq=berrenberg+lamp+factory&source=bl&ots=CnlU4nm5NC&sig=2lFTi91zpigPtbZldoKSMe8c5ro&hl=en&ei=yAMMS5jiOYvAlAfW3rmMBA&sa=X&oi=book_result&ct=result&resnum=1&ved=0CAkQ6AEwAA#v=onepage&q=berrenberg%20lamp%20factory&f=false
30) The London Gazette, 10 Jul 1900, pg 4293. http://www.london-gazette.co.uk/issues/27209/pages/4293 L-B-C Patents, Limited dissolved.
31) The London Gazette, 26 Oct 1900, pg 6560. http://www.london-gazette.co.uk/issues/27241/pages/6560 L-B-C Patents, Limited dissolved.
32) Fortschritte der Elektrotechnik, Vol 14, 1900, pp 798-799. http://books.google.com/books?id=4-rNAAAAMAAJ&pg=PA798&lpg=PA798&dq=berrenberg+southfields&source=bl&ots=dOKR8uNtwr&sig=AQ9252Xcle4zeqNT8tOvzoM9xTg&hl=en&ei=CsAAS4PaOYTWsQPk5oCICw&sa=X&oi=book_result&ct=result&resnum=5&ved=0CBQQ6AEwBA#v=onepage&q=berrenberg%20southfields&f=false
33) "Air Pump," The Engineering Magazine, Vol 19, Apr 1900, pg 298. http://books.google.com/books?id=xhHOAAAAMAAJ&pg=PA298&lpg=PA298&dq=berrenberg+air+pump+engineering+magazine&source=bl&ots=QEp4ytiYxK&sig=kkU7R5h3WwDjvPlH_hbMdi2k23Y&hl=en&ei=GuwLS7GMJdHhlAf5y9SLBA&sa=X&oi=book_result&ct=result&resnum=1&ved=0CAkQ6AEwAA#v=onepage&q=&f=false
34) Francis B. Crocker, Electric Lighting, D. Van Nostrand Company, New York, 1901, pp 402-403.
35) The London Gazette, 18 Mar 1904, pg 1808. http://www.london-gazette.co.uk/issues/27659/supplements/1808 Berrenberg Electric Lamp Syndicate dissolved.
36) The London Gazette, 2 Aug 1904, pg 4991. http://www.london-gazette.co.uk/issues/27701/pages/4991 Berrenberg Electric Lamp Syndicate dissolved.
37) "The William J. Hammer Historical Collection of Incandescent Electric Lamps," Transactions of the New York Electrical Society, New Series, No. 4, 1913, pp 15-30. The name "Berrenberg" appears on page 30.
38) Personal (R. A. Berrenberg), Lighting Journal, Vol 4, Feb 1916, pg 43. http://books.google.com/books?id=mhQAAAAAMAAJ&pg=PA43&lpg=PA43&dq=berrenberg+hoboken&source=bl&ots=0INpKnmCJ4&sig=qL9W9CQle2EsicM3t-5N6St5ZGc&hl=en&ei=Rvb9SrfGI47ysQOBv-2dCg&sa=X&oi=book_result&ct=result&resnum=1&ved=0CAkQ6AEwAA#v=onepage&q=berrenberg%20hoboken&f=false
39) Directory of Engineers - A. Berrenberg, Electrical World, Vol 72, Part 2, No. 26, 28 Dec 1918, pg 36. http://books.google.com/books?id=L60vAAAAYAAJ&pg=RA3-PA36&lpg=RA3-PA36&dq=berrenberg+vacuum+electrical+world&source=bl&ots=L4o4C1TRzW&sig=Dy8VTwOWCilZtP0ZLM_7FYtIN6E&hl=en&ei=Pi37SpfuAcSslAfdicy6Aw&sa=X&oi=book_result&ct=result&resnum=7&ved=0CBoQ6AEwBg#v=onepage&q=&f=false
40) Dr. Rüdiger Schneider Berrenberg, "Von der Bierpumpe zum Vakuum," Bergische Rundschau, 4 Jan 1986. Title translated - "From the Beer Pump to the Vacuum Pump."
41) Rüdiger Schneider Berrenberg, Solingen-Industriestadt mit Tradition, Ullrich, 1996, pg 289.
42) Matthias Kielwein and Hans-Erhard Lessing, Kaleidoskop-Fahrrad und Motorrad Technik (1895-1908), 2005, pp 107-108.
43) Communication from Dr. Rüdiger Schneider Berrenberg to Edward J. Covington, 23 Oct 2009.
44) Communication from Dr. Rüdiger Schneider Berrenberg to Edward J. Covington, 12 Nov 2009.
45) Communication from Dr. Joy Berrenberg to Edward J. Covington, 13 Jan 2010.
46) Communication from Dr. Rüdiger Schneider Berrenberg to Edward J. Covington, Mailed 15 Jan 2010.
47) Communication from Dr. Rüdiger Schneider Berrenberg to Edward J. Covington, 8 Feb 2010.
48) http://www.radium.de/downloads/chronik.html?pe_id=195 Click on Altertum-1904 box. Advance to page 10.
49) http://cdigital.dgb.uanl.mx/la/1080046951_C/1080046623_T58/1080046623_01.pdf. Pg 5.
50) http://cdigital.dgb.uanl.mx/la/1080046951_C/1080046623_T58/1080046623_16.pdf. Pages 219-220, 227-228.
51) http://cdigital.dgb.uanl.mx/la/1080046951_C/1080046623_T58/1080046623_17.pdf. Pages 231-232.
52) http://cdigital.dgb.uanl.mx/la/1080046951_C/1080046623_T58/1080046623_19.pdf. Pages 271-272.
53) International Genealogical Index - North America (Nos. 15-17). http://www.familysearch.org/Eng/Search/ancestorsearchresults.asp?last_name=Berrenberg
55) "Adolph Berrenberg (1853-1919)," unpublished family history material, by Dr. Rüdiger Schneider Berrenberg. Dr. Berrenberg is, at present, preparing a publication: "The Berrenberg Patents."