| Description | Date | Identifier | |
| Technical bulletin detailing the condition and maintenance of accumulator (battery) elements. | 2nd Dec 1927 | Box 44 \ 5 Scan024 | |
| Continued report on battery cell maintenance, focusing on charging issues with positive and negative plates. | 2nd Dec 1927 | Box 44 \ 5 Scan025 | |
| Technical note on the use of a Cadmium Electrode for assessing battery cell condition. | 2nd Dec 1927 | Box 44 \ 5 Scan026 | |
| The voltage characteristics and fault diagnosis during the charging of a battery cell. | 12th Dec 1927 | Box 44 \ 5 Scan027 | |
| Chart of readings for use with a Cadmium Electrode Voltmeter. | 12th Dec 1927 | Box 44 \ 5 Scan028 | |
| Request for a hydrometer to measure the specific gravity of petrol and accumulator electrolyte, preferably a single instrument for both jobs. | 19th Aug 1918 | Box 44 \ 5 Scan029 | |
| Responding to an enquiry about the manufacturer of a syringe type acid hydrometer. | 11th Sep 1918 | Box 44 \ 5 Scan030 | |
| To Mr. Hives regarding a quotation received for a hydrometer and comparing it to a recent purchase. | 20th Sep 1918 | Box 44 \ 5 Scan031 | |
| Letter from John J. Griffin & Sons Ltd. offering a Pipette Hydrometer for sale. | 19th Sep 1918 | Box 44 \ 5 Scan032 | |
| Requesting the purchase of four syringe-type hydrometers for battery acid. | 19th Oct 1918 | Box 44 \ 5 Scan033 | |
| Letter from a battery company regarding an out-of-stock order for hydrometer syringes. | 4th Nov 1918 | Box 44 \ 5 Scan034 | |
| Recommending the inclusion of a celluloid syringe type hydrometer in the tool kit for each chassis. | 6th Nov 1919 | Box 44 \ 5 Scan035 | |
| Sourcing celluloid syringe-type hydrometers for inclusion in the chassis tool kit. | 1st Nov 1919 | Box 44 \ 5 Scan036 | |
| Letter from Joseph Casartelli & Son requesting further particulars for a Celluloid Syringe type Hydrometer. | 15th Nov 1919 | Box 44 \ 5 Scan037 | |
| Letter from a supplier unable to fulfill an order for a Celluloid Hydrometer Syringe, redirecting to the American manufacturer. | 17th Nov 1919 | Box 44 \ 5 Scan038 | |
| Inquiry to The Chloride Electrical Storage Co. regarding Syringe type Hydrometers and the use of celluloid instead of glass. | 19th Nov 1919 | Box 44 \ 5 Scan039 | |
| Quotation from The Chloride Storage Co. Ltd. for syringe type hydrometers, with a discussion on glass versus celluloid tubes. | 20th Nov 1919 | Box 44 \ 5 Scan040 | |
| Inclusion of a syringe-type hydrometer in the tool kit and seeking approval to source them in celluloid. | 27th Nov 1919 | Box 44 \ 5 Scan041 | |
| The preference for celluloid type syringe hydrometers over glass ones for tool kits. | 28th Nov 1919 | Box 44 \ 5 Scan042 | |
| Unsuitability of a sample glass hydrometer and efforts to source a celluloid alternative. | 1st Dec 1919 | Box 44 \ 5 Scan043 | |
| Quotation letter from Luthy Hydrometer Co. for non-breakable celluloid hydrometers. | 8th Dec 1919 | Box 44 \ 5 Scan044 | |
| Request for approval to supply a hydrometer with each 40/50 Chassis kit. | 3rd Jan 1920 | Box 44 \ 5 Scan045 | |
| Request to obtain particulars for floating glass hydrometers to measure acid densities. | 15th Jan 1920 | Box 44 \ 5 Scan046 | |
| The selection and supply of hydrometers for delivered chassis. | 16th Jan 1920 | Box 44 \ 5 Scan047 | |
| Confirming the decision to supply a hydrometer with the 40/50 HP chassis kit, including for those already delivered. | 22th May 1919 | Box 44 \ 5 Scan048 | |
| Supply of celluloid syringe type hydrometers from the Luthy Hydrometer Company in America. | 16th Jan 1920 | Box 44 \ 5 Scan049 | |
| Instructing to order and supply Luthy hydrometers for all new and previously delivered chassis. | 16th Jan 1920 | Box 44 \ 5 Scan050 | |
| Letter from J. Preston regarding the availability of Hydrometers, with a subsequent order from Rolls-Royce. | 17th Jan 1920 | Box 44 \ 5 Scan051 | |
| Request to obtain two glass syringe type hydrometers for the Experimental Department from the Chloride Electrical Storage Co. | 27th Apr 1920 | Box 44 \ 5 Scan052 | |
| The supply of Luthy Hydrometers for new and previously delivered chassis. | 10th Jun 1920 | Box 44 \ 5 Scan053 | |
| Booking out of two hydrometers from the stores for the Experimental Department. | 11th Jun 1920 | Box 44 \ 5 Scan054 | |
| Instruction sheet regarding the acquisition of two hydrometers from the stores. | 14th Jun 1920 | Box 44 \ 5 Scan055 | |
| Acquisition of Luthy Products Corp. and quoting prices for their hydrometers. | 7th Nov 1922 | Box 44 \ 5 Scan056 | |
| Urgent procurement of Luthy Hydrometers or a suitable alternative. | 7th Nov 1922 | Box 44 \ 5 Scan057 | |
| The continued use of Luthy hydrometers and sourcing potential English-made alternatives. | 22th Nov 1922 | Box 44 \ 5 Scan058 | |
| The stock, pricing, and alternative suppliers for hydrometers. | 25th Nov 1922 | Box 44 \ 5 Scan059 | |
| Placing an order for a battery hydrometer with the Chloride Company and continuing with the Luthy Hydrometer. | 27th Nov 1922 | Box 44 \ 5 Scan060 | |
| Unsuitability of a sample Exide glass hydrometer for customer use due to its fragility. | 27th Nov 1922 | Box 44 \ 5 Scan061 | |
| Continuation of notes on the design features of a ribbed bulb and a float with glass prongs. | 28th Aug 1923 | Box 44 \ 5 Scan062 | |
| Comparison report on Perfection and Exide hydrometers. | 28th Aug 1923 | Box 44 \ 5 Scan063 | |
| Comparison report on Exide and Perfection make syringe hydrometers. | 18th Aug 1923 | Box 44 \ 5 Scan064 | |
| Battery tester submitted by The Runbaken Magneto Company Ltd. and its pricing. | 16th Oct 1923 | Box 44 \ 5 Scan065 | |
| The unsuitability of the Runbaken Syringe Hydrometer for chassis use following a test. | 12th Nov 1923 | Box 44 \ 5 Scan066 | |
| Re-test report on a Runbaken syringe hydrometer, comparing its accuracy against standard Twaddell hydrometers. | 31th Oct 1923 | Box 44 \ 5 Scan067 | |
| Page noting a design flaw where a rubber bulb works loose from a barrel, suggesting a locking arrangement. | 19th Nov 1923 | Box 44 \ 5 Scan068 | |
| Using the Exide Hydrometer as an alternative for the American Luthy Hydrometer. | 19th Nov 1923 | Box 44 \ 5 Scan069 | |
| Letter from The Runbaken Magneto Co. Ltd. responding to feedback on their battery tester and hydrometer. | 19th Nov 1923 | Box 44 \ 5 Scan070 | |
| Cover note regarding a letter from the Runbaken Magneto Company in reply to criticism of their Battery Tester. | 21th Nov 1923 | Box 44 \ 5 Scan071 | |
| The quality of a hydrometer sample submitted by Messrs. Runbaken for standardisation. | 22th Nov 1923 | Box 44 \ 5 Scan072 | |
| One standard Exide hydrometer to be issued from the stores. | 17th Dec 1923 | Box 44 \ 5 Scan073 | |
| Design flaws in Exide hydrometers following a comparative test. | 19th May 1924 | Box 44 \ 5 Scan074 | |
| Typed memorandum discussing improvements to a new type and the return of two hydrometers. | 9th May 1924 | Box 44 \ 5 Scan075 | |
| Comparison of a standard Exide syringe hydrometer with a new type Exide syringe hydrometer, detailing good and bad points. | 16th May 1924 | Box 44 \ 5 Scan076 | |
| Supply delay for Type S.1 hydrometers and the testing of a new sample. | 13th May 1925 | Box 44 \ 5 Scan077 | |
| Summarising tests on an Exide Hydrometer Type S1 and returning the instrument. | 15th May 1925 | Box 44 \ 5 Scan078 | |
| The Exide Hydrometer Type S1, comparing its features to the standard model. | 14th May 1925 | Box 44 \ 5 Scan079 | |
| Requesting the testing of a sample hydrometer from L.P.M.A. Co. with a handwritten cost comparison. | 12th Nov 1925 | Box 44 \ 5 Scan080 | |
| Testing and rejection of an L.P.M.A. syringe hydrometer. | 17th Nov 1925 | Box 44 \ 5 Scan081 | |
| Test report and critique of a sample L.P.M.A. Syringe Hydrometer. | 16th Nov 1925 | Box 44 \ 5 Scan082 | |
| Request to purchase two new type S.1 hydrometers, one for the Electrical Laboratory and another for private use. | 17th Dec 1925 | Box 44 \ 5 Scan083 | |
| Request to obtain three floats for S1 type hydrometers from the Chloride Elec. Storage Co. Ltd. | 19th May 1926 | Box 44 \ 5 Scan084 | |
| Comparing a U.S.A. made hydrometer with a British one, concluding the British instrument is preferred. | 25th Jun 1926 | Box 44 \ 5 Scan085 | |
| Comparison of two syringing hydrometers, an Exide model and a U.S.A. made version. | 24th Jun 1926 | Box 44 \ 5 Scan086 | |
| The testing of an Exide hydrometer, noting considerable improvement and the return of the instrument. | 7th May 1927 | Box 44 \ 5 Scan087 | |
| Review and comparison of the new type S1 Exide hydrometer. | 5th May 1927 | Box 44 \ 5 Scan088 | |
| Test report on two types of hydrometers, a float type and a syringe type. | 8th Jun 1927 | Box 44 \ 5 Scan089 | |
| Requesting the return of a faulty Exide hydrometer float for replacement. | 9th Jun 1927 | Box 44 \ 5 Scan090 | |
| Quality control procedures for externally supplied hydrometers. | 13th Jun 1927 | Box 44 \ 5 Scan091 | |
| Free of charge replacement of a faulty S.1. Hydrometer. | 15th Jun 1927 | Box 44 \ 5 Scan092 | |
| The testing of syringe hydrometers, noting they are an earlier type. | 29th Jun 1927 | Box 44 \ 5 Scan093 | |
| Instruction sheet for the loan of S1 hydrometers for testing. | 8th Sep 1927 | Box 44 \ 5 Scan094 | |
| Test report on Exide type S1 hydrometers, detailing a reading error in two of the twenty-four instruments tested. | 8th Sep 1927 | Box 44 \ 5 Scan095 | |
| Test report on 24 Exide Type S.1. Hydrometers, finding 23 to be satisfactory and one with a broken float. | 3rd Nov 1927 | Box 44 \ 5 Scan096 | |
| Request for a replacement float for an S.1. hydrometer that became jammed. | 30th Jan 1928 | Box 44 \ 5 Scan097 | |
| Confirming the price being paid for Exide type S.1 hydrometers. | 30th Jan 1928 | Box 44 \ 5 Scan098 | |
| Test report on 24 Exide Type S1 hydrometers, noting the absence of float spikes. | 31th Jan 1928 | Box 44 \ 5 Scan099 | |
| Letter from The Chloride Electrical Storage Co. Ltd. regarding design modifications to the Exide Type S.1 Hydrometer. | 7th Feb 1928 | Box 44 \ 5 Scan100 | |
| Confirming the successful testing of 25 Exide type S1 hydrometers. | 14th Feb 1928 | Box 44 \ 5 Scan101 | |
| Testing and standardisation of Exide hydrometers for production use. | 8th Mar 1928 | Box 44 \ 5 Scan102 | |
| Suggesting the withdrawal of the battery hydrometer from the standard tool kit to save costs. | 22th Nov 1928 | Box 44 \ 5 Scan103 | |
| Arguing for the inclusion of a hydrometer for testing battery electrolyte. | 13th Dec 1928 | Box 44 \ 5 Scan104 | |
| Arrangement for a semi-standard hydrometer to be returned for accuracy checks. | 5th Nov 1929 | Box 44 \ 5 Scan105 | |
| Follow-up memorandum regarding the use of syringe-type hydrometers as semi-standards for production chassis. | 30th Apr 1930 | Box 44 \ 5 Scan106 | |
| Note on the Economy Committee's decision to cease testing syringe-type hydrometers upon receipt. | 5th May 1930 | Box 44 \ 5 Scan107 | |
| Reprinted article explaining the design and operation of the D.N. Shock Absorber. | 3rd Jul 1924 | Box 44 \ 5 Scan108 | |
| Blueprint of a Type II 'Derihon' shock absorber with various cross-sections. | 11th Nov 1923 | Box 44 \ 5 Scan109 | |
| Letter to The D.N. Shock Absorber Co. requesting a blueprint and an explanation of their product's superiority over the Houdaille shock absorber. | 3rd Sep 1925 | Box 44 \ 5 Scan110 | |
| Request for samples of hydraulic shock dampers for review and discussion with Mr. Royce. | 5th Sep 1925 | Box 44 \ 5 Scan111 | |
| Letter from The D.N. Shock Absorber Co. arranging a visit to Derby. | 7th Sep 1925 | Box 44 \ 5 Scan112 | |
| Letter to The D.N. Shock Absorber Co. arranging a meeting with Mr. Hickson. | 10th Sep 1925 | Box 44 \ 5 Scan113 | |
| Derihon hydraulic shock absorber as a better proposition than the Houdaille. | 11th Sep 1925 | Box 44 \ 5 Scan114 | |
| Setup and testing of various shock dampers for the Phantom and 20 HP models. | 1st Sep 1925 | Box 44 \ 5 Scan115 | |
| Bump test report comparing Derihon, Houdaille, and Berkshire shock absorbers. | 25th Sep 1925 | Box 44 \ 5 Scan116 | |
| Comparative analysis of different shock absorbers, focusing on performance, oil leaks, and overheating issues. | 25th Sep 1925 | Box 44 \ 5 Scan117 | |
| Dunlop wheels with Goodyear demountable rims, comparing tyre stiffness and weights against a standard wheel. | 13th Nov 1919 | Box 45 \ 1 Scan001 | |
| The sourcing of straight-sided tyres for new demountable wheel rims. | 18th Mar 1920 | Box 45 \ 1 Scan002 | |
| Discussion with Mr. Royce regarding issues with Warland rims and the potential adoption of Goodyear or Firestone alternatives. | 30th Mar 1920 | Box 45 \ 1 Scan003 | |
| Replacing beaded tyres with straight-sided tyres and recommending Goodyear demountable rims. | 30th Mar 1920 | Box 45 \ 1 Scan004 | |
| Visit from Dunlop about the supply of wire wheels for straight-sided tyres. | 26th Apr 1920 | Box 45 \ 1 Scan005 | |
| Recommendation to use Dunlop wheels with Goodyear/Firestone demountable rims and straight-sided tyres, detailing their advantages. | 30th Apr 1920 | Box 45 \ 1 Scan006 | |
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