| Description | Date | Identifier | |
| Letter from a speedometer supplier confirming an agreement on instrument error margins and discussing future instrument specifications. | 29th Aug 1928 | Box 50 \ 4 Scan216 | |
| Test results for an A.T. Speedometer removed from vehicle 12-EX. | 28th Sep 1928 | Box 50 \ 4 Scan217 | |
| Request to order a non-standard speedometer for a 14G-4 car. | 22th Oct 1928 | Box 50 \ 4 Scan218 | |
| Letter to A.T. Speedometer Co. Ltd. requesting another speedometer with the same specifications as a previous one, which was reading 3% fast. | 22th Oct 1928 | Box 50 \ 4 Scan219 | |
| Suitability of Jaeger speedometers versus the currently used A.T. speedometers. | 23th Oct 1928 | Box 50 \ 4 Scan220 | |
| Calibration requirements for speedometers on the India IV chassis. | 24th Oct 1928 | Box 50 \ 4 Scan221 | |
| Instruction regarding the speedometer drive ratio calibration for India 1V cars. | 25th Oct 1928 | Box 50 \ 4 Scan222 | |
| Requesting the alteration of a speedometer's gear ratio for car 18-EX. | 1st Nov 1928 | Box 50 \ 4 Scan223 | |
| Letter to A.T. Speedometer Co. about calibrating a 20 HP speedometer to correct a distance recording error. | 25th Oct 1928 | Box 50 \ 4 Scan224 | |
| Letter from A.T. Speedometer Co. Ltd. regarding the supply of a small dial 20 HP speedometer. | 26th Oct 1928 | Box 50 \ 4 Scan225 | |
| Failing rev counter drive, suggesting it be returned to the manufacturer for redesign. | 12th Nov 1928 | Box 50 \ 4 Scan226 | |
| Log sheet detailing the testing and performance of an A.T. Speedometer. | 23th Aug 1928 | Box 50 \ 4 Scan227 | |
| Electrical experimental record sheet for an AT Speedometer. | 21th Aug 1928 | Box 50 \ 4 Scan228 | |
| Test readings for an A.T. Speedometer at various temperatures and speeds. | 23th Nov 1928 | Box 50 \ 4 Scan229 | |
| Experimental record sheet for a Bleriot A.T. Speedometer detailing reading change tests. | 30th Jan 1928 | Box 50 \ 4 Scan230 | |
| Electrical experimental record sheet for an A.T. Speedometer, detailing mileage tests. | 28th Sep 1928 | Box 50 \ 4 Scan231 | |
| Graph plotting the performance of Phantom eddy current speedometers against varying temperatures. | 10th Jan 1929 | Box 50 \ 4 Scan232 | |
| Cover sheet for a 40/50 instrument with a small type dial. | 6th Mar 1928 | Box 50 \ 4 Scan233 | |
| Communication regarding temperature compensation devices for A.T. Speedometers. | 6th Mar 1928 | Box 50 \ 4 Scan234 | |
| Extract from a memo requesting to order a specific speedometer for car 16-EX. | 20th Mar 1928 | Box 50 \ 4 Scan235 | |
| Sourcing small size A.T. speedometers for the 40/50-HP chassis. | 18th May 1928 | Box 50 \ 4 Scan236 | |
| Letter from The A.T. Speedometer Co. Ltd. regarding a delay in sending a sample instrument due to testing new magnets. | 14th May 1928 | Box 50 \ 4 Scan237 | |
| The receipt and testing of a new A.T. speedometer for the 40/50 HP chassis. | 12th Jun 1928 | Box 50 \ 4 Scan238 | |
| Letter from A.T. Speedometer Co. Ltd. regarding the testing of a speedometer with a temperature compensating device. | 8th Jun 1928 | Box 50 \ 4 Scan239 | |
| Sticking needle issue found during testing of a new A.T. Speedometer with a small type dial. | 15th Jun 1928 | Box 50 \ 4 Scan240 | |
| Extract regarding testing and performance of a speedometer instrument (B.563) for a 40/50 model. | 18th Jun 1928 | Box 50 \ 4 Scan241 | |
| Test results for A.T. Speedometer No. 563, recording performance at various temperatures and heater positions. | 4th Jul 1928 | Box 50 \ 4 Scan242 | |
| Test report on an A.T. Speedometer, noting its performance with temperature changes and a faulty trip counter. | 6th Jul 1928 | Box 50 \ 4 Scan243 | |
| Fitment of a new small type speedometer on the 40/50 HP chassis. | 11th Jul 1928 | Box 50 \ 4 Scan244 | |
| Test results for an A.T. Speedometer with a small type dial after repair of its faulty trip counter. | 28th Aug 1928 | Box 50 \ 4 Scan245 | |
| Re-testing and proposed experimental fitting of an A.T. Speedometer with a small dial. | 28th Aug 1928 | Box 50 \ 4 Scan246 | |
| Letter to A.T. Speedometer Co. Ltd. regarding the calibration of speedometers for different axle ratios. | 31th Aug 1928 | Box 50 \ 4 Scan247 | |
| Letter from A.T. Speedometer Co. Ltd. regarding the revolutions for small dial speedometers and an enquiry about standard tyre sizes. | 3rd Sep 1928 | Box 50 \ 4 Scan248 | |
| Standardisation of a small dial speedometer for the 40/50 & 20 HP models. | 3rd Sep 1928 | Box 50 \ 4 Scan249 | |
| Form for standardizing chassis parts, detailing fitment, testing, and costs. | 8th Sep 1928 | Box 50 \ 4 Scan250 | |
| Graph showing the performance of a Phantom AT Eddy Current Speedometer, plotting instrument reading against temperature. | 1st Oct 1928 | Box 50 \ 4 Scan251 | |
| Test report on an A.T. Speedometer with a small type dial, detailing reading variations and temperature effects. | 2nd Oct 1928 | Box 50 \ 4 Scan252 | |
| Correspondence regarding a faulty A.T. Revolution Counter Drive and the manufacturer's report on a new replacement Gear Box. | 28th Nov 1928 | Box 50 \ 4 Scan253 | |
| The bench re-testing of an A.T. Speedometer B.563 which showed unsteady readings. | 10th Dec 1928 | Box 50 \ 4 Scan254 | |
| Letter to The A.T. Speedometer Co. regarding the arrangement of a 40/50 HP speedometer for a car with a specific revs/mile requirement. | 1st Nov 1928 | Box 50 \ 4 Scan255 | |
| Letter from A.T. Speedometer Co. Ltd. regarding the recalibration of a speedometer to 795 revolutions. | 3rd Nov 1928 | Box 50 \ 4 Scan256 | |
| Letter to A.T. Speedometer Co. Ltd. confirming speedometer calibration for 800 revs. | 5th Nov 1928 | Box 50 \ 4 Scan257 | |
| Letter from A.T. Speedometer Co. Ltd. confirming the calibration of an instrument to 800 revs. | 6th Nov 1928 | Box 50 \ 4 Scan258 | |
| The calibration of an A.T. Speedometer for car 19EX. | 22th Nov 1928 | Box 50 \ 4 Scan259 | |
| The different speedometer drive gearbox end for the 'SS' car compared to the standard 40/50 model. | 28th Nov 1928 | Box 50 \ 4 Scan260 | |
| Blueprint detailing the components of an S.S. Speedometer Drive, including an adaptor, drive piece, and nut. | 28th Nov 1928 | Box 50 \ 4 Scan261 | |
| Urgent internal memo requesting the recalibration of a speedometer to 800 revs/mile. | 12th Dec 1928 | Box 50 \ 4 Scan262 | |
| Order for a custom 20 HP speedometer with specific calibration and a cream dial. | 5th Dec 1928 | Box 50 \ 4 Scan263 | |
| Electrical experimental record sheet for an A.T. Speedometer. | 24th Feb 1928 | Box 50 \ 4 Scan264 | |
| The performance and testing of an A.T. Speedometer from a 40/50 car. | 7th Dec 1928 | Box 50 \ 4 Scan265 | |
| The re-testing of an A.T. Speedometer which was found to have an unsteady reading. | 10th Dec 1928 | Box 50 \ 4 Scan266 | |
| Faulty A.T. speedometer being sent back to the manufacturer for analysis. | 10th Dec 1928 | Box 50 \ 4 Scan267 | |
| Note about sending a small type T. speedometer to Hoopers for an experimental enclosed limousine. | 13th Dec 1928 | Box 50 \ 4 Scan268 | |
| The examination of a faulty speedometer, quoting findings and repair costs from the manufacturer. | 14th Dec 1928 | Box 50 \ 4 Scan269 | |
| Instructions to despatch a speedometer for conversion to read correctly for chassis 20.EX. | 19th Dec 1928 | Box 50 \ 4 Scan270 | |
| Complaint regarding a non-waterproof A.T. Speedometer No. B.563 which was damaged after letting in water on an 8-EX car. | 20th Dec 1928 | Box 50 \ 4 Scan271 | |
| Water leak in a speedometer caused by a split rubber washer, with a suggestion for a solid ring washer replacement. | 20th Dec 1928 | Box 50 \ 4 Scan272 | |
| Complaint and repair costs for a non-water-tight A.T. Speedometer, model B.563. | 21th Dec 1928 | Box 50 \ 4 Scan273 | |
| The condition of a speedometer, attaching a reply from the A.T. Speedometer Co. Ltd. | 29th Dec 1928 | Box 50 \ 4 Scan274 | |
| Letter from A.T. Speedometer Co. Ltd. responding to an inquiry about condensation in an instrument. | 31th Dec 1928 | Box 50 \ 4 Scan275 | |
| Faulty A.T. Speedometer B.563, discussing water ingress and a subsequent issue with a slipping needle. | 31th Dec 1928 | Box 50 \ 4 Scan276 | |
| Communication regarding a replace order for a speedometer and a request to dismantle the instrument. | 7th Jan 1929 | Box 50 \ 4 Scan277 | |
| Letter from a speedometer supplier regarding the inspection of a returned instrument and an invoice adjustment. | 2nd Jan 1929 | Box 50 \ 4 Scan278 | |
| The closing part of a letter from A.T. Speedometer Co. Ltd. | 9th Jan 1929 | Box 50 \ 4 Scan279 | |
| Fault found during bench testing of an A.T. Speedometer P.563. | 9th Jan 1929 | Box 50 \ 4 Scan280 | |
| The Jaeger speedometer, advising against standardization but allowing it as a customer-specific option. | 10th Jan 1929 | Box 50 \ 4 Scan281 | |
| Confirming that Speedometer No. B.563 has been inspected and found to be O.K. | 14th Jan 1929 | Box 50 \ 4 Scan282 | |
| Testing of A.T. speedometers and returning a faulty one for correction. | 18th Jan 1929 | Box 50 \ 4 Scan283 | |
| From the Experimental Department arranging the return of instrument No.C.296 to The A.T. Speedometer Co. Ltd. | 19th Jan 1929 | Box 50 \ 4 Scan284 | |
| Test failure report for an improved revolution counter drive and a request for a replacement. | 25th Jan 1929 | Box 50 \ 4 Scan285 | |
| Report from the A.T. Speedometer Co. Ltd. regarding the diagnosis and repair of a faulty speedometer. | 25th Jan 1929 | Box 50 \ 4 Scan286 | |
| Faulty Bleriot A.T. Speedometer that is sticking and needs to be returned to the makers. | 22th Mar 1929 | Box 50 \ 4 Scan287 | |
| Letter from A.T. Speedometer Co. Ltd. concerning a damaged replacement speedometer, believed to be caused by a heavy blow. | 25th Mar 1929 | Box 50 \ 4 Scan288 | |
| Works order confirmation from A.T. Speedometer Co. Ltd. regarding a faulty speedometer. | 25th Mar 1929 | Box 50 \ 4 Scan289 | |
| The order of a clock and speedometer with cream dials for chassis 16-G4. | 7th May 1929 | Box 50 \ 4 Scan290 | |
| Modification to the casing for a speedometer and clock. | 8th May 1929 | Box 50 \ 4 Scan291 | |
| Letter from A.T. Speedometer Co. Ltd. confirming an order and clarifying required modifications to an instrument. | 10th May 1929 | Box 50 \ 4 Scan292 | |
| Letter from A.T. Speedometer Co. Ltd. regarding an alteration to a Die Cast Case. | 10th May 1929 | Box 50 \ 4 Scan293 | |
| Urgent memo specifying the requirements for a 20 HP speedometer for car 17-GIV. | 5th May 1929 | Box 50 \ 4 Scan294 | |
| Test report on various A.T. Speedometer models fitted to experimental cars. | 1st May 1929 | Box 50 \ 4 Scan295 | |
| Test report on an A.T. Speedometer No. A728, detailing accuracy over a temperature range. | 30th May 1929 | Box 50 \ 4 Scan296 | |
| Calculations for Phantom & S.S. speedometer drive ratios. | 31th May 1929 | Box 50 \ 4 Scan297 | |
| Test report for an A.T. speedometer, showing readings at various temperatures. | 12th Jun 1929 | Box 50 \ 4 Scan298 | |
| Letter to A.T. Speedometer Co. Ltd. concerning excessive temperature variations in supplied speedometers. | 26th Jun 1929 | Box 50 \ 4 Scan299 | |
| Requesting a speedometer from car 14-EX for laboratory testing after completing a mileage test. | 26th Jun 1929 | Box 50 \ 4 Scan300 | |
| Requesting a retest for an A.T. Speedometer, number 728, on car 14-EX. | 26th Jun 1929 | Box 50 \ 4 Scan301 | |
| Letter from A.T. Speedometer Co. Ltd. regarding speedometer temperature variation limits and testing Instrument No.A.728. | 28th Jun 1929 | Box 50 \ 4 Scan302 | |
| Recommendation on speedometer standards for S.S. and 20 HP models to ensure accurate readings with different rim sizes. | 4th Jul 1929 | Box 50 \ 4 Scan303 | |
| The testing and specifications of A.T. speedometers for 20 HP and 40/50 HP models. | 7th Jul 1929 | Box 50 \ 4 Scan304 | |
| Test results on an instrument's speed reading accuracy at various temperatures. | 9th Jul 1929 | Box 50 \ 4 Scan305 | |
| Temperature test report for an A.T. speedometer on a 20 HP chassis. | 9th Jul 1929 | Box 50 \ 4 Scan306 | |
| Temperature variation tests of an S.S. speedometer for a 40/50 HP vehicle. | 22th Jul 1929 | Box 50 \ 4 Scan307 | |
| Experimental record sheet for an A.T. Speedometer, detailing mileage tests. | 27th Sep 1928 | Box 50 \ 4 Scan308 | |
| Notification about the alteration of the R.P.M. for the 40/50 HP Chassis speedometer. | 18th Sep 1929 | Box 50 \ 4 Scan309 | |
| Query regarding a discrepancy in S.S. Chassis speedometer drive gear ratio calculations. | 20th Sep 1929 | Box 50 \ 4 Scan310 | |
| S.S. chassis speedometer accuracy, drive ratio calculations, and a proposal for alternative instruments. | 25th Sep 1929 | Box 50 \ 4 Scan311 | |
| Directive to recalibrate speedometers for the 20 HP chassis due to the use of larger diameter tyres. | 17th Oct 1929 | Box 50 \ 4 Scan312 | |
| Query and response regarding the approved figure for road wheel revolutions per mile for 20/25 HP tyres. | 28th Oct 1929 | Box 50 \ 4 Scan313 | |
| Letter to Mr. Minchin of Messrs. Peto & Radford concerning a speedometer gearing and reading discrepancy. | 28th Oct 1929 | Box 50 \ 4 Scan314 | |
| Page 2 of a letter to Messrs. Peto & Radford concerning an instrument discrepancy. | 28th Oct 1929 | Box 50 \ 4 Scan315 | |
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