| Description | Date | Identifier | |
| Letter from The Economic Car Light Ltd. introducing their new Automatic Dashboard Petrol Indicator. | 24th Mar 1930 | Box 61 \ 3 scan0019 | |
| Letter from 'THE ECONOMIC CAR LIGHT LIMITED' offering to supply standard indicator and tank fitments. | 24th Mar 1930 | Box 61 \ 3 scan0020 | |
| Reliability and installation of a new clock-faced petrol gauge, comparing it to existing instruments. | 5th Apr 1930 | Box 61 \ 3 scan0021 | |
| Letter to The Nivex Gauge Co. Ltd. regarding instrument tests, parts supply, and specifications for 20 HP and 40/50 cars. | 9th Apr 1930 | Box 61 \ 3 scan0022 | |
| Sending a Cambridge Thermometer and a K.S. Petrol Gauge Tank Unit to Nivex Gauge Co. Ltd. for inspection. | 9th Apr 1930 | Box 61 \ 3 scan0023 | |
| Letter from Nivex Gauge Limited regarding the examination of a tank unit and the development of a new fitment for 20HP and 40/50HP models. | 14th Apr 1930 | Box 61 \ 3 scan0024 | |
| Invoices from S. Smith & Sons for a Calorstat and Smithermets, requesting guidance on how to proceed with the debits. | 28th Apr 1930 | Box 61 \ 3 scan0025 | |
| Invoice from S.Smith and Sons Ltd. for a Calorstat sample. | 24th Apr 1930 | Box 61 \ 3 scan0026 | |
| Letter from H.M. Hobson Ltd. regarding the dispatch of two die tools for the Telegage pressure balance connection. | 5th May 1930 | Box 61 \ 3 scan0027 | |
| Letter from H.M. Hobson, Ltd. confirming an arrangement for a 45-degree back tube connection and gauge submission. | 5th May 1930 | Box 61 \ 3 scan0028 | |
| The delivery schedule for petrol gauges from Nivex Gauge Ltd. | 9th May 1930 | Box 61 \ 3 scan0029 | |
| Letter from Nivex Gauge Limited regarding the despatch of a specially made petrol gauge. | 8th May 1930 | Box 61 \ 3 scan0030 | |
| Sourcing a special fuel gauge suitable for American conditions. | 16th May 1930 | Box 61 \ 3 scan0031 | |
| The order of K.S. gauges for the L.H. chassis from Messrs H.M. Hobson Ltd. | 24th May 1930 | Box 61 \ 3 scan0032 | |
| Letter from H.M. Hobson Limited regarding the shipment and delivery of two gauges. | 22th May 1930 | Box 61 \ 3 scan0033 | |
| Request to H.M. Hobson Ltd. for the supply of petrol gauge heads for an experimental car. | 4th Jun 1930 | Box 61 \ 3 scan0034 | |
| Covering note for an attached letter from Messrs. H. M. Hobson Limited regarding two K.S. gauges ordered for a Phantom II. | 4th Jun 1930 | Box 61 \ 3 scan0035 | |
| Letter from H.M. Hobson Limited regarding the supply and modification of American K-S gauges for a 40/50 HP tank. | 2nd Jun 1930 | Box 61 \ 3 scan0036 | |
| Return of a model petrol gauge to Messrs. Smith & Sons, Ltd. | 4th Jun 1930 | Box 61 \ 3 scan0037 | |
| Letter from H.M. Hobson, Ltd. regarding the supply of Telegage dash units for experimental cars. | 5th Jun 1930 | Box 61 \ 3 scan0038 | |
| Dispatch of K.S. petrol gauge parts for inspection. | 5th Jun 1930 | Box 61 \ 3 scan0039 | |
| Complaints and a temporary modification for fixing the K.S. petrol gauge. | 6th Jun 1930 | Box 61 \ 3 scan0040 | |
| Letter from H.M. Hobson, Ltd. regarding modifications to a speedometer type fixing and a new die cast frame. | 14th Jun 1930 | Box 61 \ 3 scan0041 | |
| Letter from H.M. Hobson Ltd. regarding modifications and parts for a 20/25 HP model. | 14th May 1930 | Box 61 \ 3 scan0042 | |
| Improvements to the design of a petrol gauge. | 16th Jun 1930 | Box 61 \ 3 scan0043 | |
| List of suggestions for improvements to a tank and gauge system, including anti-spillage measures. | 16th Jun 1930 | Box 61 \ 3 scan0044 | |
| Continued discussion on tank design options, fittings, and venting systems. | 16th Jun 1930 | Box 61 \ 3 scan0045 | |
| Letter from H.M. Hobson, Ltd. regarding the urgent dispatch of a gauge head. | 18th Jun 1930 | Box 61 \ 3 scan0046 | |
| Letter from H.M. Hobson, Ltd. regarding instrument delivery and an enclosed sketch for modification K.S.630.D. | 18th Jun 1930 | Box 61 \ 3 scan0047 | |
| Drawing of a rectangular instrument unit with a hairpin spring fixing mechanism. | 16th Jun 1930 | Box 61 \ 3 scan0048 | |
| Delivery and payment authorization for a pump from S.A. Cutters Ltd. | 19th Jun 1930 | Box 61 \ 3 scan0049 | |
| Requesting that a Nivex gauge be brought to WW on Tuesday. | 21th Jun 1930 | Box 61 \ 3 scan0050 | |
| Causes of petrol gauge failures and the subsequent modifications tested. | 24th Jun 1930 | Box 61 \ 3 scan0051 | |
| The technical issues and improvements of the 'Nivex' and 'Claudel Hobson' petrol gauges. | 24th Jun 1930 | Box 61 \ 3 scan0052 | |
| The merits and fitting procedures of the 'Nivex' petrol gauge. | 24th Jun 1930 | Box 61 \ 3 scan0053 | |
| Concluding page of a typed document comparing a product to those available in the United States. | 28th Jun 1930 | Box 61 \ 3 scan0054 | |
| Investigation into the statistics and causes of petrol gauge failures, with proposed modifications. | 28th Jun 1930 | Box 61 \ 3 scan0055 | |
| Improvements and issues with petrol gauges, comparing Hobson and Nivex models. | 28th Jun 1930 | Box 61 \ 3 scan0056 | |
| The advantages and fitting procedures of the 'Nivex' pressure gauge. | 28th Jun 1930 | Box 61 \ 3 scan0057 | |
| 'Niver' gauge and its potential standardisation after completing 10,000 miles. | 28th Jun 1930 | Box 61 \ 3 scan0058 | |
| Letter to H.M. Hobson Ltd. regarding a potential safety issue with permanently soldered air lines on a rear tank unit. | 26th Jun 1930 | Box 61 \ 3 scan0059 | |
| Standardisation of the K.S. petrol gauge with an improved glass tube seal for chassis parts. | 30th Apr 1930 | Box 61 \ 3 scan0060 | |
| Instructed changes for a petrol gauge and a related petrol tank design. | 27th Jun 1930 | Box 61 \ 3 scan0061 | |
| Letter from H.M. Hobson, Ltd. discussing the dangers of a specific tank unit design. | 30th Jun 1930 | Box 61 \ 3 scan0062 | |
| Proposed design modification for a tank unit, detailing its assembly and testing requirements. | 30th Jun 1930 | Box 61 \ 3 scan0063 | |
| Letter from H.M. Hobson, Ltd. regarding the testing and fitting of sample units and protective covers for tank components. | 30th Jun 1930 | Box 61 \ 3 scan0064 | |
| Letter confirming the dispatch of new 20 HP and 40/50 HP heads and requesting the return of the old parts for reuse. | 30th Jun 1930 | Box 61 \ 3 scan0065 | |
| Letter to H.M. Hobson, Ltd. regarding modifications to gauge heads for tank units. | 1st Jul 1930 | Box 61 \ 3 scan0066 | |
| Letter discussing the redesign of a rear fuel tank, including changes to the filler, vent, and pump system. | 1st Jul 1930 | Box 61 \ 3 scan0067 | |
| Despatch of old K.S. petrol gauge heads to Messrs. H.M. Hobson for part exchange. | 1st Jul 1930 | Box 61 \ 3 scan0068 | |
| Modifications to the petrol gauge and instrument panel for easier installation and maintenance. | 1st Jul 1930 | Box 61 \ 3 scan0069 | |
| Design of the instrument board for the 2nd L.H. Chassis (25-EX) to meet USA requirements. | 1st Jul 1930 | Box 61 \ 3 scan0070 | |
| Letter from H.M. Hobson, Ltd. discussing the design of a petrol gauge head. | 4th Jul 1930 | Box 61 \ 3 scan0071 | |
| Letter discussing the simplification and modification of a gauge and tank unit design. | 4th Jul 1930 | Box 61 \ 3 scan0072 | |
| Letter discussing the re-design of a rear tank, focusing on the placement of a unit with a central baffle and Sprengel pumping tubes. | 4th Jul 1930 | Box 61 \ 3 scan0073 | |
| Letter from H. M. Hobson Ltd. discussing the placement, design, and testing of a vented tank unit. | 4th Jul 1930 | Box 61 \ 3 scan0074 | |
| Letter to H.M. Hobson Ltd. regarding Mr. Royce's decision not to alter a car's rear tank and the consequences for an improved gauge. | 7th Jul 1930 | Box 61 \ 3 scan0075 | |
| Internal memorandum requesting an order for one K.S. Telegauge from Messrs. H.M. Hobson Ltd. | 9th Jul 1930 | Box 61 \ 3 scan0076 | |
| Letter from H.M. Hobson, Ltd. regarding a tank and gauge installation, with a suggestion from the King-Seeley Corporation. | 10th Jul 1930 | Box 61 \ 3 scan0077 | |
| Modifying and testing a pressure balance bell and tank vent installation. | 10th Jul 1930 | Box 61 \ 3 scan0078 | |
| Page 3 of a letter from H.M. Hobson, Ltd. discussing a gauge head scale. | 10th Jul 1930 | Box 61 \ 3 scan0079 | |
| Letter from H.M. Hobson Ltd. confirming the dispatch of a gauge head by parcel post. | 20th Jun 1930 | Box 61 \ 3 scan0080 | |
| Letter from H.M. Hobson, Ltd. regarding a sample single-line unit mock-up for inspection. | 29th Jul 1930 | Box 61 \ 3 scan0081 | |
| Positioning, venting, and pressure testing of a tank unit. | 29th Jul 1930 | Box 61 \ 3 scan0082 | |
| Letter from H.M. Hobson, Ltd. regarding pumping trials of a unit using a volatile spirit. | 29th Jul 1930 | Box 61 \ 3 scan0083 | |
| Letter to Messrs. H.M. Hobson Ltd. regarding a promising tank unit to be shown to Mr. Royce. | 12th Aug 1930 | Box 61 \ 3 scan0084 | |
| Letter from H.M. Hobson Ltd. discussing design points and test rigs for a supplied unit. | 13th Aug 1930 | Box 61 \ 3 scan0085 | |
| Letter discussing comparative testing of a new external pumping tube design to address fuel system issues. | 13th Aug 1930 | Box 61 \ 3 scan0086 | |
| The final page of a letter concerning comparative tests for a car. | 13th Aug 1930 | Box 61 \ 3 scan0087 | |
| Condemned radiator for car 18-GIV and a new tank unit for a petrol telegauge. | 3rd Mar 1930 | Box 61 \ 3 scan0088 | |
| Modifications to the petrol tank, reserve tank, and luggage grids for the rear of the car. | 14th Aug 1930 | Box 61 \ 3 scan0089 | |
| Design of luggage grids and rear aprons for cars. | 14th Aug 1930 | Box 61 \ 3 scan0090 | |
| Development and testing of a new experimental K.S. petrol gauge and tank unit from Messrs. Hobson. | 14th Aug 1930 | Box 61 \ 3 scan0091 | |
| Test report on a centrally vented tank unit, concluding that a second balance line is not required. | 1st Aug 1930 | Box 61 \ 3 scan0092 | |
| Continued document page detailing requirements for a fuel tank unit's positioning, baffling, and venting. | 14th Aug 1930 | Box 61 \ 3 scan0093 | |
| Design details and standardisation of the K.S. petrol gauge tank fitting. | 26th Aug 1930 | Box 61 \ 3 scan0094 | |
| Design alterations for a K.S. petrol gauge tank fitting. | 6th Sep 1930 | Box 61 \ 3 scan0095 | |
| Letter to H.M. Hobson Ltd. detailing two difficulties with gauges they are supplying for production. | 8th Sep 1930 | Box 61 \ 3 scan0096 | |
| Letter from H.M. Hobson Ltd. discussing the design constraints and modifications for incorporating a fused seal into an existing instrument. | 11th Sep 1930 | Box 61 \ 3 scan0097 | |
| Manufacturing variations in gauge glasses and proposed solutions to improve accuracy. | 11th Sep 1930 | Box 61 \ 3 scan0098 | |
| Test procedure for comparing fuel gauges with different tapered glass. | 11th Sep 1930 | Box 61 \ 3 scan0099 | |
| Letter from H. M. Hobson Ltd. discussing issues with a tank unit and a blocked air pump tube. | 11th Sep 1930 | Box 61 \ 3 scan0100 | |
| Letter from H.M. Hobson Ltd. regarding the dispatch of gauge heads and a modified tank unit for testing. | 12th Sep 1930 | Box 61 \ 3 scan0101 | |
| Page 2 of a letter from H.M. Hobson, Ltd. regarding material quality and advice note labeling. | 12th Sep 1930 | Box 61 \ 3 scan0102 | |
| Letter from H.M. Hobson Ltd. arranging a meeting for Captain Dodson to discuss a fuel feed problem for aircraft. | 15th Sep 1930 | Box 61 \ 3 scan0103 | |
| Page 2 of a letter to W.A. Robotham concerning a fuel feed problem and the need for co-operation between relevant parties. | 15th Sep 1930 | Box 61 \ 3 scan0104 | |
| Issues and tests related to Hobson K.S. Telegauge petrol gauges on Phantom II and 20/25HP chassis. | 23th Sep 1930 | Box 61 \ 3 scan0105 | |
| Letter to Major Searight of Messrs. H. M. Hobson Ltd. regarding a delayed response and arranging a meeting in Derby. | 23th Sep 1930 | Box 61 \ 3 scan0106 | |
| Letter to H.M. Hobson Ltd. regarding issues with inaccurate gauge heads and defective pump tubes. | 25th Sep 1930 | Box 61 \ 3 scan0107 | |
| Letter regarding a customer's dissatisfaction with multiple faulty car gauges. | 25th Sep 1930 | Box 61 \ 3 scan0108 | |
| Letter from H.M. Hobson, Ltd. proposing a meeting on October 1st. | 25th Sep 1930 | Box 61 \ 3 scan0109 | |
| Sending two K.S. petrol gauge heads for despatch to Messrs. H. M. Hobson for return to the makers. | 26th Sep 1930 | Box 61 \ 3 scan0110 | |
| Letter to H.M. Hobson Ltd. rescheduling a meeting due to a trip to the Paris Salon. | 27th Sep 1930 | Box 61 \ 3 scan0111 | |
| Confirming the return of faulty Hobson K.S.Telegauge heads for a Phantom II chassis due to an incorrect glass taper. | 27th Sep 1930 | Box 61 \ 3 scan0112 | |
| Letter from supplier H.M. Hobson, Ltd. confirming a requested meeting on October 7th. | 29th Sep 1930 | Box 61 \ 3 scan0113 | |
| Letter from H.M. Hobson Ltd. acknowledging receipt of two Telegage heads and clarifying that no credit will be passed. | 30th Sep 1930 | Box 61 \ 3 scan0114 | |
| Letter from H.M. Hobson Ltd. proposing a new scheme for an aeroplane fuel pump. | 6th Oct 1930 | Box 61 \ 3 scan0115 | |
| Description of a fuel system scheme and a list of enclosed blueprint diagrams. | 6th Oct 1930 | Box 61 \ 3 scan0116 | |
| Aircraft fuel system challenges, including fuel supply interruption during manoeuvres and pump gas locks. | 6th Oct 1930 | Box 61 \ 3 scan0117 | |
| Concluding letter page from H.M. Hobson Ltd offering co-operation on aeroplane experiments. | 6th Oct 1930 | Box 61 \ 3 scan0118 | |
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