| Description | Date | Identifier | |
| Letter to H.M. Hobson Ltd. regarding the removal of an overflow pipe on a 40/50 HP model. | 14th Jun 1928 | Box 44 \ 2 Scan147 | |
| The standardisation and fitting of a Claudel Hobson petrol gauge on the 20 HP model. | 14th Jun 1928 | Box 44 \ 2 Scan148 | |
| Letter from H.M. Hobson Ltd. regarding the installation of a Hobson K-S Telegauge on a 20 HP model. | 13th Jun 1928 | Box 44 \ 2 Scan149 | |
| Letter from H.M. Hobson Ltd. confirming they will produce a complete set incorporating a Sprengel unit for trial. | 15th Jun 1928 | Box 44 \ 2 Scan150 | |
| Letter from H.M. Hobson, Ltd. discussing the deletion and modification of a vent pipe on a gauge. | 15th Jun 1928 | Box 44 \ 2 Scan151 | |
| Letter advising against deleting an overflow pipe due to potential fuel gauge issues related to atmospheric pressure. | 15th Jun 1928 | Box 44 \ 2 Scan152 | |
| Letter from H.M. Hobson, Ltd. regarding vent pipe design requirements and potential liability for gauges. | 15th Jun 1928 | Box 44 \ 2 Scan153 | |
| Letter to H.M.Hobson Ltd. regarding a disagreement over the necessity of a vent pipe for a tank gauge, which Mr. Royce finds unsightly. | 18th Jun 1928 | Box 44 \ 2 Scan154 | |
| Letter from H.M. Hobson, Ltd. requesting the loan of a tank for experiments with their K-S Telegage unit. | 19th Jun 1928 | Box 44 \ 2 Scan155 | |
| Letter from H.M. Hobson, Ltd. requesting diagrams for a gauge installation and discussing collaboration with the King-Seeley Corporation. | 19th Jun 1928 | Box 44 \ 2 Scan156 | |
| Letter to Claudel Hobson Ltd. concerning a petrol tank, K-S petrol gauge, and the tilting angle of a Sprengel pumping unit for a 20 HP vehicle. | 28th Jun 1928 | Box 44 \ 2 Scan157 | |
| Letter from H.M. Hobson Ltd. regarding a petrol tank and the Hobson K-S Telegage. | 29th Jun 1928 | Box 44 \ 2 Scan158 | |
| Letter discussing modifications to a unit with tubes, cups, and a bell to suit specific conditions. | 29th Jun 1928 | Box 44 \ 2 Scan159 | |
| Letter from H.M. Hobson, Ltd. discussing the arrangement of Sprengel cups within a 20 HP fuel tank. | 29th Jun 1928 | Box 44 \ 2 Scan160 | |
| Letter to H.M. Hobson, Ltd. regarding drawings for a petrol gauge and requesting a unit for testing. | 2nd Jul 1928 | Box 44 \ 2 Scan161 | |
| Letter from H.M. Hobson, Ltd. arranging an appointment to discuss an experimental Hobson K-S Telegage. | 4th Jul 1928 | Box 44 \ 2 Scan162 | |
| The second page of a letter from H.M. Hobson, Ltd. regarding a planned departure time. | 4th Jul 1928 | Box 44 \ 2 Scan163 | |
| Fitment issues of a K-S petrol gauge on an instrument board. | 6th Jul 1928 | Box 44 \ 2 Scan164 | |
| Process for standardising and costing the Claudel Hobson petrol gauge. | 6th Jul 1928 | Box 44 \ 2 Scan165 | |
| Letter from H.M. Hobson Ltd. regarding drawings for unions, air line piping, and tank units for 20 HP and 40/50 HP cars. | 6th Jul 1928 | Box 44 \ 2 Scan166 | |
| Letter discussing a non-standard tank, potential modifications, and the re-working of a gauge set from a 40/50 HP chassis. | 6th Jul 1928 | Box 44 \ 2 Scan167 | |
| Letter from H.M. Hobson, Ltd. recommending the use of a motor hand tyre pump for drying air lines. | 6th Jul 1928 | Box 44 \ 2 Scan168 | |
| Teething troubles with the King-Seely petrol gauge, focusing on pressure build-up and pipeline unions. | 7th Jul 1928 | Box 44 \ 2 Scan169 | |
| Instruction to return a K-S Petrol Gauge Dashboard Unit to Messrs. Claudel Hobson for modification. | 9th Jul 1928 | Box 44 \ 2 Scan170 | |
| Letter from H.M. Hobson, Ltd. confirming an arrangement to shorten the Hobson K-S Telegage instrument. | 12th Jul 1928 | Box 44 \ 2 Scan171 | |
| The engineering merits and installation of an equalizer bell and line for petrol gauges. | 12th Jul 1928 | Box 44 \ 2 Scan172 | |
| Page 3 of a letter from H.M. Hobson, Ltd. regarding a patented equalizer system for industrial and aeroplane gauges. | 12th Jul 1928 | Box 44 \ 2 Scan173 | |
| Letter to Claudel Hobson Ltd. regarding tests and modifications for a K-S petrol gauge intended for Mr. Royce's car. | 12th Jul 1928 | Box 44 \ 2 Scan174 | |
| Letter discussing the urgent supply of a new tank unit and a top casting for a car. | 13th Jul 1928 | Box 44 \ 2 Scan175 | |
| Letter to H.M. Hobson Ltd. regarding issues and modifications to a K-S Telegage. | 13th Jul 1928 | Box 44 \ 2 Scan176 | |
| Letter from H.M. Hobson, Ltd. to Rolls-Royce, Ltd. regarding an enclosed diagram. | 13th Jul 1928 | Box 44 \ 2 Scan177 | |
| Sketch showing a shortened dash unit and pressure balance for a 40-50HP model. | 13th Jul 1928 | Box 44 \ 2 Scan178 | |
| Improved design for the Hobson Petrol Gauge featuring a new air seal. | 14th Jul 1928 | Box 44 \ 2 Scan179 | |
| Letter from H.M. Hobson, Ltd. regarding a Hobson K-S Telegage and a top casting for Mr. Royce's car. | 14th Jul 1928 | Box 44 \ 2 Scan180 | |
| Letter from H.M. Hobson, Ltd. discussing arrangements for a tank unit and requesting the facia board angle for Mr. Royce's car. | 14th Jul 1928 | Box 44 \ 2 Scan181 | |
| From H.M. Hobson Ltd. confirming a wire chasing an order for a special tank unit top casting. | 16th Jul 1928 | Box 44 \ 2 Scan182 | |
| Request for a sketch of the Hobson Petrol Gauge to fit it into a new instrument patch. | 17th Jul 1928 | Box 44 \ 2 Scan183 | |
| Typed memo regarding the fitting of K-S petrol gauges and potential obstructions for front seat occupants. | 17th Jul 1928 | Box 44 \ 2 Scan184 | |
| Modification to the K-S petrol gauge design by Claudel Hobson. | 17th Jul 1928 | Box 44 \ 2 Scan185 | |
| Letter from H.M. Hobson Ltd. regarding the calibration and final installation of a gauge on Mr. Royce's car by their representative, Mr. Holt. | 18th Jul 1928 | Box 44 \ 2 Scan186 | |
| Letter to H.M. Hobson Ltd. requesting blueprints for a balance unit for 20 HP and 40/50 HP models. | 19th Jul 1928 | Box 44 \ 2 Scan187 | |
| Letter discussing a persistent petrol gauge issue with Major Searight of Claudel Hobson's, and sending a new unit for testing. | 19th Jul 1929 | Box 44 \ 2 Scan188 | |
| Disappointing radiator test results comparing new and old tube types. | 20th Jul 1928 | Box 44 \ 2 Scan189 | |
| Letter from H.M. Hobson, Ltd. regarding a blueprint for dash units and modifications to a casting for tank units. | 20th Jul 1928 | Box 44 \ 2 Scan190 | |
| Letter regarding the installation of a gauge in a car, the dispatch of a blueprint, and coordination with coachbuilders. | 20th Jul 1928 | Box 44 \ 2 Scan191 | |
| Letter from H.M. Hobson, Ltd. enclosing a blueprint for 20 HP and 40/50 HP dash units. | 21th Jul 1928 | Box 44 \ 2 Scan192 | |
| Blueprint for a 40-50 HP 20 Gallon De Luxe (P.B.) Dash Unit. | 21th Jul 1928 | Box 44 \ 2 Scan193 | |
| Fault with the K-S petrol gauge and a proposed modification for improved air venting. | 23th Jul 1928 | Box 44 \ 2 Scan194 | |
| Modification to the 40/50 HP petrol tank filler to improve air release when refuelling. | 23th Jul 1928 | Box 44 \ 2 Scan195 | |
| Letter regarding a revised mask or dial for an instrument fitted to Mr. Royce's car. | 23th Jul 1928 | Box 44 \ 2 Scan196 | |
| Letter from H.M. Hobson, Ltd. concerning the supply of instruments and modified top castings. | 23th Jul 1928 | Box 44 \ 2 Scan197 | |
| Modifications to a casting for a Hobson petrol gauge to enable a full tank reading. | 24th Jul 1928 | Box 44 \ 2 Scan198 | |
| Complaining about the inaccuracy and uselessness of a petrol gauge on vehicle 10-G3. | 26th Jul 1928 | Box 44 \ 2 Scan199 | |
| Letter to H.M. Hobson Ltd. regarding the supply and modification of Hobson Telegage units for a 40/50 HP car. | 13th Aug 1928 | Box 44 \ 2 Scan200 | |
| Letter to H.M. Hobson Ltd. regarding a leaking gauge, testing findings, and recommendations for improving rubber quality. | 13th Aug 1929 | Box 44 \ 2 Scan201 | |
| The second page of a letter confirming a follow-up correspondence regarding a gauge. | 14th Aug 1928 | Box 44 \ 2 Scan202 | |
| Letter from H.M. Hobson Ltd. regarding the supply of two Telegages and the necessary modifications required. | 14th Aug 1928 | Box 44 \ 2 Scan203 | |
| Letter from H.M. Hobson Ltd. discussing tank alterations for gauges, enclosing a print of a special top plate, and mentioning Mr. Royce's car. | 14th Aug 1928 | Box 44 \ 2 Scan204 | |
| Blueprint of a casting for a component, showing multiple views and connections for an air line and an equaliser line. | 14th Aug 1928 | Box 44 \ 2 Scan205 | |
| Letter regarding the return of a failed Gauge head for investigation. | 15th Aug 1939 | Box 44 \ 2 Scan206 | |
| Letter from H.M. Hobson, Ltd. regarding a modification to the Telegage dash board unit. | 18th Aug 1928 | Box 44 \ 2 Scan207 | |
| Letter to H.M. Hobson Ltd. regarding the modification of tanks to take the top plate casting KS.1640 for the 40/50 HP model. | 17th Aug 1928 | Box 44 \ 2 Scan208 | |
| Letter from H.M. Hobson Ltd. regarding pressure balance gauges for 40/50 HP cars. | 31th Aug 1928 | Box 44 \ 2 Scan209 | |
| Instructions for testing a liquid gauge instrument on a car under acceleration. | 31th Aug 1928 | Box 44 \ 2 Scan210 | |
| Letter to H.M. Hobson Ltd. regarding issues with faulty old type gauges on experimental cars. | 1st Sep 1928 | Box 44 \ 3 Scan001 | |
| Letter from H.M. Hobson, Ltd. regarding faulty K-S Telegages causing excessive overnight loss on customer cars. | 4th Sep 1928 | Box 44 \ 3 Scan002 | |
| Letter discussing the troubleshooting of Temple and Sprengel type tank units and their potential replacement. | 4th Sep 1928 | Box 44 \ 3 Scan003 | |
| Letter from H.M. Hobson, Ltd. requesting details on the installation of pressure balance type units. | 4th Sep 1928 | Box 44 \ 3 Scan004 | |
| Letter from H.M. Hobson, Ltd. arranging a meeting in Derby regarding the Hobson K-S Telegage. | 17th Sep 1928 | Box 44 \ 3 Scan005 | |
| Letter to H.M. Hobson Ltd. arranging a meeting and reporting leaking and erratically functioning gauges. | 18th Sep 1928 | Box 44 \ 3 Scan006 | |
| Optimal positioning of the K-S Telegage in the tank for 20 HP and 40/50 HP models. | 19th Sep 1928 | Box 44 \ 3 Scan007 | |
| The K-S Telegage petrol gauge for the 20 HP and 40/50 models. | 21th Sep 1928 | Box 44 \ 3 Scan008 | |
| The incorrect positioning of the Telegage and filter on the 12-EX tank. | 21th Sep 1928 | Box 44 \ 3 Scan009 | |
| Letter from H.M. Hobson Ltd. discussing further trials and potential modifications for Telegages. | 21th Sep 1928 | Box 44 \ 3 Scan010 | |
| Letter discussing air pumping tests, petrol levels, and the replacement of a Sprengel unit with a new double-capacity version. | 21th Sep 1928 | Box 44 \ 3 Scan011 | |
| The K-S petrol gauge in the tank of 10-EX be moved. | 1st Sep 1928 | Box 44 \ 3 Scan012 | |
| Letter to H.M. Hobson Ltd. regarding cooperation on testing to improve the functioning of a gauge. | 22th Sep 1928 | Box 44 \ 3 Scan013 | |
| The correct procedure for fitting K-S petrol gauges to avoid unsatisfactory behaviour. | 24th Sep 1928 | Box 44 \ 3 Scan014 | |
| Letter from H.M. Hobson Ltd. discussing the probable cause of an excessive over-night loss, attributing it to insufficient air pumping. | 24th Sep 1928 | Box 44 \ 3 Scan015 | |
| Page 2 of a letter from H.M. Hobson Ltd. concerning test results on a unit's bell capacity and petrol loss. | 24th Sep 1928 | Box 44 \ 3 Scan016 | |
| Letter from H.M. Hobson, Ltd. regarding the dispatch of three tank units with increased bell capacity and associated drawings. | 25th Sep 1928 | Box 44 \ 3 Scan017 | |
| Page two of a letter from H. M. Hobson Ltd. discussing pump performance and arranging a follow-up visit. | 25th Sep 1928 | Box 44 \ 3 Scan018 | |
| Letter to H.M. Hobson Ltd. discussing the performance of telegauges, noting an immunity from trouble, and requesting new balance line assemblies. | 26th Sep 1928 | Box 44 \ 3 Scan019 | |
| Untraceable telegauges and a related invoice from H. M. Hobson, Ltd. | 27th Sep 1928 | Box 44 \ 3 Scan020 | |
| Querying how to proceed with invoices for Telegauges from H. M. Hobson Ltd. for which no order was issued. | 20th Sep 1928 | Box 44 \ 3 Scan021 | |
| Letter from H.M. Hobson Ltd. regarding overnight loss on Telegage installations due to temperature drops and condensation. | 27th Sep 1928 | Box 44 \ 3 Scan022 | |
| Letter from H.M. Hobson, Ltd. regarding a pressure balance telegage set and a meeting in Paris. | 27th Sep 1928 | Box 44 \ 3 Scan023 | |
| The fitting and standardisation of K-S and Hobson Telegages. | 1st Oct 1928 | Box 44 \ 3 Scan024 | |
| Instructions for fitting K-S petrol gauges to avoid unsatisfactory behaviour. | 1st Sep 1928 | Box 44 \ 3 Scan025 | |
| Covering order for two balanced type gauges for the 40/50 HP car. | 28th Sep 1928 | Box 44 \ 3 Scan026 | |
| Internal request to order a K-S petrol gauge unit for a 40/50 HP model from H.M. Hobson Ltd. | 28th Sep 1928 | Box 44 \ 3 Scan027 | |
| Following up on an untraced order for a Telegage from H.M. Hobson, Ltd. | 28th Sep 1928 | Box 44 \ 3 Scan028 | |
| Letter from supplier H.M. Hobson Ltd. regarding an invoice charge for a Telegage. | 24th Sep 1928 | Box 44 \ 3 Scan029 | |
| Instructions for fitting a K.S. Gauge to the petrol tank for a 12-EX Chassis. | 24th Sep 1928 | Box 44 \ 3 Scan030 | |
| Request for a quote and recommendation on fitting a K.S. Telegauge to a 20 HP chassis for Guy Knowles Esq. | 8th Oct 1928 | Box 44 \ 3 Scan031 | |
| Recommendation for a K-S gauge with a twin pipe which provides a pressure balance. | 8th Oct 1928 | Box 44 \ 3 Scan032 | |
| The cancellation of the 'K.S.' Telegauge standardisation due to functional issues, reverting to the old type. | 8th Oct 1928 | Box 44 \ 3 Scan033 | |
| Letter to H.M. Hobson Ltd. regarding a fault with a balanced gauge on a 40/50 HP car. | 17th Oct 1928 | Box 44 \ 3 Scan034 | |
| Letter from H.M. Hobson Ltd. acknowledging a query regarding a balanced gauge on a 40/50 HP car. | 18th Oct 1928 | Box 44 \ 3 Scan035 | |
| Letter from H.M. Hobson Ltd. discussing the performance of a balanced fuel gauge on a 40/50 HP car. | 19th Oct 1928 | Box 44 \ 3 Scan036 | |
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