| Description | Date | Identifier | |
| Letter from H.M. Hobson Ltd. responding to a complaint about an unsightly taper on a gauge and proposing design changes. | 7th Oct 1930 | Box 61 \ 3 scan0119 | |
| Letter addressing issues with gauges, including bezel-less installation, blocked flexible tubes, and returned parts. | 7th Oct 1930 | Box 61 \ 3 scan0120 | |
| Letter from H.M. Hobson, Ltd. about the successful repair of a leaky gauge on Mr. Fairey's car. | 7th Oct 1930 | Box 61 \ 3 scan0121 | |
| Sending particulars of French Guichard petrol indicators. | 10th Oct 1930 | Box 61 \ 3 scan0122 | |
| French language brochure for a Guichard patented remote continuous fuel level indicator. | 10th Oct 1930 | Box 61 \ 3 scan0123 | |
| French-language description and schematic for a patented fuel level transmitter and receiver system. | 15th Oct 1930 | Box 61 \ 3 scan0124 | |
| Use of English speedometers on chassis destined for the USA. | 15th Oct 1930 | Box 61 \ 3 scan0125 | |
| Confirming the acceptance of A.T. speedometers for the first 75 L.H. chassis for the U.S.A. | 16th Oct 1930 | Box 61 \ 3 scan0126 | |
| Trial of a tank unit with a larger internal diameter pump tube for the Hobson K.S. Telegauges on Phantom II and 20/25HP chassis. | 17th Oct 1930 | Box 61 \ 3 scan0127 | |
| Letter to H.M. Hobson Ltd. regarding the modification of gauge heads and a tank unit. | 21th Oct 1930 | Box 61 \ 3 scan0128 | |
| Despatch of gauge heads and a tank unit to Messrs. H.M. Hobson, Ltd. | 21th Oct 1930 | Box 61 \ 3 scan0129 | |
| Letter from H.M. Hobson, Ltd. regarding the modernization of parts for experimental cars. | 24th Oct 1930 | Box 61 \ 3 scan0130 | |
| Request for a preliminary report on the Nivex Gauge for comparison against the standard Telegage. | 29th Oct 1930 | Box 61 \ 3 scan0131 | |
| Letter from H.M. Hobson, Ltd. discussing a new aeroplane fuel pump scheme and the potential for carburettor freezing. | 4th Nov 1930 | Box 61 \ 3 scan0132 | |
| Letter discussing the provision of a carburetter for an experiment, either by adapting an existing one or designing a new one. | 4th Nov 1930 | Box 61 \ 3 scan0133 | |
| Implementation of a centrally vented tank to simplify the petrol gauge. | 7th Nov 1930 | Box 61 \ 3 scan0134 | |
| Letter to H.M. Hobson, Ltd. regarding a blueprint for an experimental tank design with a central vent. | 1st Dec 1930 | Box 61 \ 3 scan0135 | |
| Despatch of a loaned K.S. tank unit to Messrs. H.M. Hobson, Ltd. | 1st Dec 1930 | Box 61 \ 3 scan0136 | |
| Letter from H.M. Hobson Ltd. regarding an experimental tank design and the return of a sample unit. | 3rd Dec 1930 | Box 61 \ 3 scan0137 | |
| Letter from H.M. Hobson, Ltd. discussing modifications to an experimental fuel tank to improve petrol pumping and manage surge. | 3rd Dec 1930 | Box 61 \ 3 scan0138 | |
| Covering memo for a letter received from Messrs. H.M. Hobson Ltd. | 5th Dec 1930 | Box 61 \ 3 scan0139 | |
| Alterations to a K.S. Petrol Gauge from the U.S.A., specifically eliminating the reserve on the scale. | 6th Dec 1930 | Box 61 \ 3 scan0140 | |
| Letter from H.M. Hobson, Ltd. regarding the despatch of an experimental single line tank unit. | 11th Dec 1930 | Box 61 \ 3 scan0141 | |
| Discoloration of liquid in Hobson K-S Telegages due to using incorrect adjustment tools. | 17th Dec 1930 | Box 61 \ 3 scan0142 | |
| Letter from H.M. Hobson Ltd. regarding an investigation into why recording fluid in a Hobson K-S Telegage is turning black. | 16th Dec 1930 | Box 61 \ 3 scan0143 | |
| Letter from H.M. Hobson Ltd about the unsuitability of a wire for use with Acetylene Tetrabromide fluid. | 17th Dec 1930 | Box 61 \ 3 scan0144 | |
| Letter from H.M. Hobson, Ltd. regarding the dispatch of an experimental single line gauge set and a complementary instrument for testing. | 17th Dec 1930 | Box 61 \ 3 scan0145 | |
| Technical memorandum discussing fuel tank venting arrangements and gauge head markings. | 17th Dec 1930 | Box 61 \ 3 scan0146 | |
| Fuel tank capacity, gauge accuracy, and servicing procedures. | 17th Dec 1930 | Box 61 \ 3 scan0147 | |
| Technical letter detailing the procedure for correcting a vehicle's gauge. | 17th Dec 1930 | Box 61 \ 3 scan0148 | |
| Page 5 of a letter from H.M. Hobson, Ltd. regarding a tank installation for an experimental set. | 17th Dec 1930 | Box 61 \ 3 scan0149 | |
| Letter from H.M. Hobson Ltd. regarding the enclosure of a piece of tubing. | 19th Dec 1930 | Box 61 \ 3 scan0150 | |
| Letter from H.M. Hobson Ltd. regarding a confidential, experimental Telegage set. | 19th Dec 1930 | Box 61 \ 3 scan0151 | |
| Request for a further report on a Nivex Gauge supplied for testing purposes. | 24th Dec 1930 | Box 61 \ 3 scan0152 | |
| Proposal to change Phantom II speedometers from showing 90 m.p.h. to 100 m.p.h. and a query about the impact on the American market. | 1st Jan 1931 | Box 61 \ 3 scan0153 | |
| Response regarding the modification of speedometers to read up to 100 M.P.H. | 9th Jan 1931 | Box 61 \ 3 scan0154 | |
| Calibration diagram for a Hobson K.S. Telegage, single line type. | 7th Mar 1931 | Box 61 \ 3 scan0155 | |
| Follow-up request for a report on a Nivex Gauge that was supplied for testing purposes. | 14th Jan 1931 | Box 61 \ 3 scan0156 | |
| Testing and subsequent rejection of a Nivex Gauge. | 16th Jan 1931 | Box 61 \ 3 scan0157 | |
| The failures of the Nivex Gauge, listing numerous complaints and returns, and suggesting investigation into alternatives. | 21th Jan 1931 | Box 61 \ 3 scan0158 | |
| Request for testing instructions for a Claudel Hobson Aeroplane Fuel Pump, with attached drawings. | 9th Mar 1931 | Box 61 \ 3 scan0159 | |
| Letter to H.M. Hobson Ltd. regarding the delayed testing of an aeroplane fuel pump and carburetter developments. | 9th Mar 1931 | Box 61 \ 3 scan0160 | |
| Issues with the petrol gauge and rear apron on the Phantom II model. | 9th Mar 1931 | Box 61 \ 3 scan0161 | |
| Complaints related to petrol gauges and their potential causes. | 9th Mar 1931 | Box 61 \ 3 scan0162 | |
| Letter to H.M. Hobson, Ltd. regarding the testing and design issues of a K.S. Petrol Gauge. | 9th Mar 1931 | Box 61 \ 3 scan0163 | |
| Advantages and disadvantages of a centrally vented petrol tank compared to the current design. | 13th Mar 1931 | Box 61 \ 3 scan0164 | |
| Letter from H.M. Hobson Ltd. regarding the scale calibration for a Hobson K-S Petrol Telegage. | 13th Mar 1931 | Box 61 \ 3 scan0165 | |
| Design of a fuel gauge, considering factors like fuel type, surge during acceleration, and dial dimensions. | 13th Mar 1931 | Box 61 \ 3 scan0166 | |
| Letter from H.M. Hobson, Ltd. discussing the design and placement of a tank vent and filler to prevent petrol vapour odours. | 13th Mar 1931 | Box 61 \ 3 scan0167 | |
| Letter to Major Searight of Messrs. H.M.Hobson Ltd., discussing the design and development of a single line tank unit. | 23th Mar 1931 | Box 61 \ 3 scan0168 | |
| Letter from H.M. Hobson Ltd. arranging a meeting to discuss and resolve difficulties. | 25th Mar 1931 | Box 61 \ 3 scan0169 | |
| Letter to Messrs H.M. Hobson Ltd. confirming a meeting and extending a lunch invitation to Major Searight. | 26th Mar 1931 | Box 61 \ 3 scan0170 | |
| Letter from H.M. Hobson, Ltd. to W.A. Robotham regarding a lunch meeting arrangement. | 28th Mar 1931 | Box 61 \ 3 scan0171 | |
| Rejection of a petrol gauge design and a proposal for a new version for an experimental tank. | 31th Mar 1931 | Box 61 \ 3 scan0172 | |
| Outlining rig test requirements for remote-driven, oil-driven, and air-driven petrol and hot-well pumps for aeroplanes. | 31th Mar 1931 | Box 61 \ 3 scan0173 | |
| Tests and modifications for compressed air systems and water-driven hot-well pumps. | 15th Sep 1931 | Box 61 \ 3 scan0174 | |
| Schematic diagram for the tackle of a Claudel Hobson petrol pump. | 15th Sep 1931 | Box 61 \ 3 scan0175 | |
| Letter to Messrs. H.M. Hobson Ltd. regarding issues with the fluid in K.S. gauge heads losing its colour. | 8th May 1931 | Box 61 \ 3 scan0176 | |
| Letter from H.M. Hobson Ltd. concerning the discolouration of K-S Telegage fluid dye. | 9th May 1931 | Box 61 \ 3 scan0177 | |
| Correspondence from H.M. Hobson Ltd. about issues with fading liquid in gauges and proposed testing methods. | 9th May 1931 | Box 61 \ 3 scan0178 | |
| Correspondence from H.M. Hobson Ltd. regarding the fading of liquid in Telegage gauges. | 15th May 1931 | Box 61 \ 3 scan0179 | |
| Letter discussing an investigation into ultra-violet ray resisting glass to prevent the fading of red liquid in gauges. | 15th May 1931 | Box 61 \ 3 scan0180 | |
| Page 3 of a letter from H.M. Hobson, Ltd. discussing a glass sample with UV-blocking properties. | 15th May 1931 | Box 61 \ 3 scan0181 | |
| Letter to H.M. Hobson Ltd. concerning the fading of liquid in gauges, particularly the effects of sunlight and fuse glass. | 19th May 1931 | Box 61 \ 3 scan0182 | |
| Despatch of unsatisfactory telegauge fluid to Messrs H.M. Hobson for inspection. | 21th May 1931 | Box 61 \ 3 scan0183 | |
| Letter from H. M. Hobson Ltd. regarding an investigation into fading liquid in gauges believed to be caused by sunlight exposure. | 21th May 1931 | Box 61 \ 3 scan0184 | |
| Letter from H.M. Hobson, Ltd. inquiring about chassis gauges and discussing the design of a tank unit. | 21th May 1931 | Box 61 \ 3 scan0185 | |
| Letter discussing investigations into fading liquid in gauges and changes to its chemical composition. | 21th May 1931 | Box 61 \ 3 scan0186 | |
| Letter from H.M. Hobson Ltd. discussing a proposed arrangement for a single line gauge, referring to Sketch No.204, to manage anti-splash and overflow conditions. | 22th May 1931 | Box 61 \ 3 scan0187 | |
| Fuel tank design modifications to prevent spillage and improve component arrangement. | 22th May 1931 | Box 61 \ 3 scan0188 | |
| Concluding page of a letter from H.M. Hobson, Ltd. requesting remarks on suggested arrangements. | 22th May 1931 | Box 61 \ 3 scan0189 | |
| Blueprint of a fuel tank with a filler neck, internal float mechanism, and outlet valve. | 22th May 1921 | Box 61 \ 3 scan0190 | |
| Return of a small bottle of K.S. gauge fluid to Messrs. H.M. Hobson for examination. | 27th May 1931 | Box 61 \ 3 scan0191 | |
| Letter to Messrs. H.M. Hobson regarding the dispatch of faded K.S. fluid samples. | 27th May 1931 | Box 61 \ 3 scan0192 | |
| Letter from H.M. Hobson Ltd. regarding a sketch and the arrangement for a vent pipe. | 28th May 1931 | Box 61 \ 3 scan0193 | |
| Postscript to a letter discussing a clearance issue between a vent pipe and a tank. | 28th May 1931 | Box 61 \ 3 scan0194 | |
| Letter to H.M. Hobson Ltd. regarding the arrangement for a vent pipe union and testing a tank. | 29th May 1931 | Box 61 \ 3 scan0195 | |
| Despatch of a K.S. fluid test tube to H.M. Hobson Ltd. for examination. | 1st Jun 1931 | Box 61 \ 3 scan0196 | |
| Letter to Messrs. H.M. Hobson regarding a fluid sample from an experimental car's petrol gauge which has lost its colour. | 1st Jun 1931 | Box 61 \ 3 scan0197 | |
| Letter from H.M. Hobson, Ltd. discussing the specific gravity and colour change of a fluid sample from an experimental car. | 3rd Jun 1931 | Box 61 \ 3 scan0198 | |
| Letter from H.M. Hobson, Ltd. regarding tests on a liquid and recommending the use of Crooks' glass. | 3rd Jun 1931 | Box 61 \ 3 scan0199 | |
| Letter from H.M. Hobson, Ltd. regarding modifications to a petrol tank for the installation of a single-line gauge. | 10th Jun 1931 | Box 61 \ 3 scan0200 | |
| Technical letter discussing fuel tank testing, pumping conditions, and a proposed curved Telegage surge baffle. | 10th Jun 1931 | Box 61 \ 3 scan0201 | |
| Page 3 of a letter from H.M. Hobson, Ltd. discussing the incorporation of a surge baffle into a tank. | 10th Jun 1931 | Box 61 \ 3 scan0202 | |
| 40/50 tank returned from Claudel Hobsons for baffle modification and completion. | 17th Jun 1931 | Box 61 \ 3 scan0203 | |
| Letter from H.M. Hobson Ltd. recommending the use of Crookes 'A' glass in instruments to prevent the fading of liquid. | 25th Jun 1931 | Box 61 \ 3 scan0204 | |
| Fading and darkening issues of the liquid used in gauges, referencing King-Seeley Corporation tests. | 25th Jun 1931 | Box 61 \ 3 scan0205 | |
| Letter from H.M. Hobson, Ltd. discussing liquid discoloration in gauges, potential causes like water contamination, and solutions such as using Crookes glass. | 25th Jun 1931 | Box 61 \ 3 scan0206 | |
| Letter to H.M. Hobson Ltd. concerning the fitting of instruments to a tank and arranging a follow-up visit. | 30th Jun 1931 | Box 61 \ 3 scan0207 | |
| Letter from H.M. Hobson Ltd. regarding a visit to discuss the adoption of Crookes' glass. | 1st Jul 1931 | Box 61 \ 3 scan0208 | |
| Letter from H.M. Hobson Ltd. regarding Telegage trouble and improvements at the Cricklewood depot. | 9th Jul 1931 | Box 61 \ 3 scan0209 | |
| Letter from H.M. Hobson, Ltd. discussing instruments for the Phantom II model. | 9th Jul 1931 | Box 61 \ 3 scan0210 | |
| List of 40/50 HP cars fitted with modified Telegage heads. | 9th Jul 1931 | Box 61 \ 3 scan0211 | |
| Letter from H.M. Hobson, Ltd. regarding the supply and sending of parts for a gauge on Mr. Royce's car. | 9th Jul 1931 | Box 61 \ 3 scan0212 | |
| Letter to W.A. Robotham explaining a potential cause for a fuel gauge inaccuracy issue related to air locking. | 9th Jul 1931 | Box 61 \ 3 scan0213 | |
| Letter to W.A. Robotham regarding a gauge test, a possible explanation for a calibration issue, and a spare unit. | 9th Jul 1931 | Box 61 \ 3 scan0214 | |
| Illustration showing an air lock in a fuel tank affecting the fuel capacity reading. | 15th Jul 1931 | Box 61 \ 3 scan0215 | |
| Letter from H.M. Hobson Ltd. regarding a sample skeleton top for a single-line Telegage unit and test findings. | 15th Jul 1931 | Box 61 \ 3 scan0216 | |
| Page 2 of a letter from H.M. Hobson, Ltd. regarding the servicing of a gauge. | 15th Jul 1931 | Box 61 \ 3 scan0217 | |
| Quarterly complaints about the reliability of petrol gauges. | 22th Jul 1931 | Box 61 \ 3 scan0218 | |
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