| Description | Date | Identifier | |
| Test data tables showing pull force vs. extension and plunger rise vs. temperature. | 4th May 1933 | Box 39 \ 4 Scan315 | |
| Performance charts for the Gallay 'Hercule' thermostat, showing force, temperature, and extension relationships. | 4th May 1933 | Box 39 \ 4 Scan316 | |
| The cover sheet of a document from the Print Room in Derby. | 6th May 1933 | Box 39 \ 4 Scan317 | |
| Supplier's list for Radiator Guards for the Bensport Chassis. | 17th May 1933 | Box 39 \ 4 Scan318 | |
| Flight tests of thermostatic radiator shutters on a Fury aircraft. | 29th Jun 1933 | Box 39 \ 4 Scan319 | |
| Graph comparing radiator temperature on glide with manually vs. thermostatically operated shutters for a Fury K.2035 aircraft. | 28th Jun 1933 | Box 39 \ 4 Scan320 | |
| The reverse of a document showing a 'Print Room' stamp. | 30th Jun 1933 | Box 39 \ 4 Scan321 | |
| The return of thermostats to Packless Gland Co. and ordering replacements. | 11th Jul 1933 | Box 39 \ 4 Scan322 | |
| Letter to The Packless Gland Co. Ltd. regarding issues with thermostats and a request for new samples to be made to specific figures. | 11th Jul 1933 | Box 39 \ 4 Scan323 | |
| Letter to The Packless Gland Co. Ltd. regarding the testing of thermostats and a suggestion to copy an existing design. | 29th Jul 1933 | Box 39 \ 4 Scan324 | |
| Flight tests of thermostatic shutters on a 'Fury' aircraft. | 29th Jul 1933 | Box 39 \ 4 Scan325 | |
| Graph comparing the performance of hand operated and automatically operated thermostatic shutters during a glide from 15,000 feet. | 25th Jul 1932 | Box 39 \ 4 Scan326 | |
| Reverse of a document showing a print room stamp from Derby. | 31th Jul 1933 | Box 39 \ 4 Scan327 | |
| Setting of thermostatic shutters and their application to water-cooled engines. | 4th Aug 1933 | Box 39 \ 4 Scan328 | |
| Letter from The Packless Gland Co. Ltd. seeking feedback on supplied thermostats and following up on a quote for flexible glands. | 18th Sep 1933 | Box 39 \ 4 Scan329 | |
| Letter to The Packless Gland Co. Ltd. explaining a delay in reporting thermostat results. | 20th Sep 1933 | Box 39 \ 4 Scan330 | |
| Letter from the Experimental Dept. to The Packless Gland Co. Ltd. regarding the testing of thermostats and glands. | 28th Sep 1933 | Box 39 \ 4 Scan331 | |
| Internal request to order four Bentley thermostats from the Packless Gland Co Ltd. | 28th Sep 1933 | Box 39 \ 4 Scan332 | |
| Letter from S. Smith & Sons enclosing a 1934 booklet on Thermostatic Devices. | 19th Oct 1933 | Box 39 \ 4 Scan333 | |
| Pricing of thermostats from The Packless Gland Company compared to S.Smith & Sons. | 13th Nov 1933 | Box 39 \ 4 Scan334 | |
| Performance of a Packless Gland Co. thermostat and the commencement of a 10,000-mile test. | 16th Nov 1933 | Box 39 \ 4 Scan335 | |
| Query about a device for automatically closing radiator shutters to keep the engine warm when stationary. | 27th Nov 1933 | Box 39 \ 4 Scan336 | |
| Tests on Bentley radiator shutters that fail to open correctly in cold weather at high speeds. | 8th Dec 1933 | Box 39 \ 4 Scan337 | |
| Letter to The Packless Gland Co. Ltd. regarding a change in material specification for a bellows end piece. | 14th Dec 1933 | Box 39 \ 4 Scan338 | |
| Force measurements from spring balance and road tests on Bentley Radiator Shutters. | 8th Dec 1933 | Box 39 \ 4 Scan339 | |
| Performance testing of different calorstats for radiator shutters. | 19th Dec 1933 | Box 39 \ 4 Scan340 | |
| Performance issues with radiator shutters on Bentley cars and considerations for the upcoming Spectre model. | 29th Dec 1933 | Box 39 \ 4 Scan341 | |
| Summary of the disadvantages of using radiator shutters, arguing for an alternative design. | 29th Dec 1933 | Box 39 \ 4 Scan342 | |
| Modification to the Bentley starting handle and radiator shutters. | 2nd Jan 1934 | Box 39 \ 4 Scan343 | |
| Calorstat tests comparing a 'Packless Gland' Co. type with a 'Smith's Standard' type. | 9th Jan 1934 | Box 39 \ 4 Scan344 | |
| Graph comparing the performance of Smith's 'H' Filling Standard Production and 'Packless Gland' type Calorstats. | 27th Dec 1933 | Box 39 \ 4 Scan345 | |
| Stamp from the Print Room in Derby. | 9th Jan 1934 | Box 39 \ 4 Scan346 | |
| Graph comparing calorstat tests between a Smith's 'H' Filling and a 'Packless Gland' type. | 27th Dec 1933 | Box 39 \ 4 Scan347 | |
| Back page with a Print Room stamp from the Derby facility. | 9th Jan 1934 | Box 39 \ 4 Scan348 | |
| Testing of increased leverage on thermostatic radiator shutters for a Bentley vehicle. | 25th Jan 1934 | Box 39 \ 4 Scan349 | |
| The alteration and experimental trial of Bentley radiator shutters. | 7th Feb 1934 | Box 39 \ 4 Scan350 | |
| Radiator shutters for the Phantom II and 20/25 HP chassis and their unsuitability for the Bentley. | 8th Feb 1934 | Box 39 \ 4 Scan351 | |
| The design of a tunnel and cover for the starting handle hole on Bentley radiator shutters. | 23th Feb 1934 | Box 39 \ 4 Scan352 | |
| Letter to S. Smith & Sons requesting thermostats for experimental fitting to a Kestrel aero engine. | 23th Feb 1934 | Box 39 \ 4 Scan353 | |
| Inquiry to The British Thermostat Co. Ltd. about supplying thermostats for a Kestrel aero engine. | 23th Feb 1934 | Box 39 \ 4 Scan354 | |
| Letter from The British Thermostat Co. Ltd. discussing thermostat placement and by-pass options for an engine. | 26th Feb 1934 | Box 39 \ 4 Scan355 | |
| Letter from The British Thermostat Co. Ltd. promising to send details of recommended instruments. | 26th Feb 1934 | Box 39 \ 4 Scan356 | |
| Letter from S. Smith & Sons regarding the design of a thermostat with balance valves. | 26th Feb 1934 | Box 39 \ 4 Scan357 | |
| Letter from S. Smith & Sons regarding the testing of thermostats for a Kestrel aero engine. | 5th Mar 1934 | Box 39 \ 4 Scan358 | |
| Letter from S. Smith & Sons regarding a new thermostat design with balanced valves for the Kestrel aero engine. | 23th Mar 1934 | Box 39 \ 4 Scan359 | |
| Letter to S. Smith & Sons to arrange a discussion regarding a thermostat for Kestrel Aero Engines. | 27th Mar 1934 | Box 39 \ 4 Scan360 | |
| Modification to the radiator shutters to allow for starting handle access on P.2, 20/25, and Bentley models. | 29th Mar 1934 | Box 39 \ 4 Scan361 | |
| Radiator shutter arrangement to accommodate the starting handle on P.2, 20/25, and Bentley models. | 29th Mar 1934 | Box 39 \ 4 Scan362 | |
| Introduction of a starting handle tunnel with cover for the Phantom II and 20/25 HP chassis. | 5th Apr 1934 | Box 39 \ 4 Scan363 | |
| Unbalanced shutters on the Bentley and their effect on wind pressure issues. | 29th Jun 1934 | Box 39 \ 4 Scan364 | |
| Requesting the testing and evaluation of new pressure gauges against a competitor's product. | 30th Oct 1913 | Box 40 \ 1 Scan001 | |
| Letter from supplier Negretti & Zambra regarding their inability to supply the 'Acrometer' due to war mobilisation. | 31th Jan 1918 | Box 40 \ 1 Scan002 | |
| Letter to Messrs. Negretti & Zambra enquiring about the partial supply of a Compression and Explosion Pressure Indicator. | 11th Feb 1918 | Box 40 \ 1 Scan003 | |
| Letter from instrument makers Negretti & Zambra regarding difficulties repairing Acrometers due to wartime mobilisation of staff. | 14th Feb 1918 | Box 40 \ 1 Scan004 | |
| 'eggshell' dull black finish with silver lettering for oil and fuel pressure gauges, as required by Mr. Royce. | 5th May 1919 | Box 40 \ 1 Scan005 | |
| Recommendation to change the oil pressure gauge for the 40/50 chassis by removing the red warning mark. | 27th May 1919 | Box 40 \ 1 Scan006 | |
| Two sample fuel gauges supplied by Messrs. Salter, now with the Experimental Department. | 30th May 1919 | Box 40 \ 1 Scan007 | |
| Recommending the removal of the red mark on pressure gauges for oil and fuel. | 30th May 1919 | Box 40 \ 1 Scan008 | |
| Query regarding the removal of the red mark on the fuel gauge dial due to changes in fuel pump pressure. | 29th May 1919 | Box 40 \ 1 Scan009 | |
| The instrument board fuel gauge and the operation of the air pressure pump. | 5th Jun 1919 | Box 40 \ 1 Scan010 | |
| Request from Mr. Royce to trial pressure gauges with luminous hands for visibility in the dark. | 13th Aug 1919 | Box 40 \ 1 Scan011 | |
| Trial of new, better-finished, and cheaper oil and fuel gauges supplied by J. Benson Ltd. | 3rd Sep 1919 | Box 40 \ 1 Scan012 | |
| Required black finish for pressure gauges from supplier J. Benson Ltd. | 8th Sep 1919 | Box 40 \ 1 Scan013 | |
| Request to disassemble and examine the finish of oil and fuel pressure gauges from Bensons Ltd. and Salters. | 27th Sep 1919 | Box 40 \ 1 Scan014 | |
| Design of new oil and fuel pressure gauges from supplier Bensons. | 15th Oct 1919 | Box 40 \ 1 Scan015 | |
| Design feedback for oil and fuel pressure gauges supplied by J.W. Benson Ltd. | 16th Oct 1919 | Box 40 \ 1 Scan016 | |
| To Mr. Mills requesting an enquiry for a Threfall Micrometer Water Gauge from the Cambridge Scientific Instrument Co. | 21th Oct 1918 | Box 40 \ 1 Scan017 | |
| Letter from scientific instrument makers Negretti & Zambra regarding overload gauges. | 31th Oct 1919 | Box 40 \ 1 Scan018 | |
| Letter from Negretti & Zambra discussing Acrometers and Manographs, noting slow manufacture and high prices. | 31th Oct 1919 | Box 40 \ 1 Scan019 | |
| Promotional leaflet for 'Overload' pressure gauges and related instruments for internal combustion engines. | 6th Nov 1934 | Box 40 \ 1 Scan020 | |
| Product information sheet detailing various types, specifications, and prices for overload gauges used in motor engines. | 14th Nov 1919 | Box 40 \ 1 Scan021 | |
| Higher oil pressures to reduce piston knocks and the need for updated gauges. | 14th Nov 1919 | Box 40 \ 1 Scan022 | |
| Increasing the range of oil pressure gauges from 20 lbs to 30 lbs. | 28th Nov 1919 | Box 40 \ 1 Scan023 | |
| Increasing the pressure range on oil gauges for the 40/50 HP chassis. | 22th May 1919 | Box 40 \ 1 Scan024 | |
| Sample oil and fuel gauges supplied by Bensons for a chassis instrument board. | 23th Dec 1919 | Box 40 \ 1 Scan025 | |
| List of new parts fitted to a car for a 10,000-mile run, with remarks on the reasons for the changes. | 5th Jan 1920 | Box 40 \ 1 Scan026 | |
| The satisfactory performance of oil and pressure gauges supplied by Bensons for a 10,000-mile test car. | 1st Jan 1920 | Box 40 \ 1 Scan027 | |
| Standardisation sheet for an oil gauge registering up to 30 lbs. | 10th Jan 1920 | Box 40 \ 1 Scan028 | |
| Requesting review of a standardisation sheet for an oil gauge registering up to 30 Lbs. | 15th Jan 1920 | Box 40 \ 1 Scan029 | |
| Cover memo for a standardisation sheet on an oil gauge registering up to 30 lbs. | 20th Jan 1920 | Box 40 \ 1 Scan030 | |
| Standardisation of an oil gauge registering up to 30 lbs, supplied by Messrs. Benson. | 10th Jan 1920 | Box 40 \ 1 Scan031 | |
| Discontinuation of Benson pressure gauges and the quality of Salter's alternative product. | 29th Jan 1920 | Box 40 \ 1 Scan032 | |
| Quotation received for a LeClair petrol gauge for the 40/50 HP chassis. | 4th Jul 1922 | Box 40 \ 1 Scan033 | |
| Quotation and licensing proposal for a patented petrol gauge from L.J. LeClair. | 1st Jun 1922 | Box 40 \ 1 Scan034 | |
| Letter from L.J. LeClair outlining terms for the manufacture and sale of the 'LeClair Petrol Gauge'. | 27th Nov 1922 | Box 40 \ 1 Scan035 | |
| Request to obtain a price list for pressure gauges with a non-return valve from Messrs. Negretti & Zambra. | 27th Nov 1922 | Box 40 \ 1 Scan036 | |
| Selection of an 'Acrometer' from Messrs. Negretti and Zambra, specifying desired pressure ranges and requesting more information. | 1st Jan 1923 | Box 40 \ 1 Scan037 | |
| Order for a 60 m/m dial pattern gauge, known as an 'Acrometer', for cold readings. | 1st Jan 1923 | Box 40 \ 1 Scan038 | |
| Letter to supplier Negretti & Zambra regarding an 'Acrometer' gauge that was smaller than anticipated. | 16th Feb 1923 | Box 40 \ 1 Scan039 | |
| Letter to Negretti & Zambra concerning an 'Acrometer' Pressure Gauge, returning another gauge, and asking about valves. | 20th Feb 1923 | Box 40 \ 1 Scan040 | |
| The return of an unsuitable 'Acrometer' gauge to the supplier. | 20th Feb 1923 | Box 40 \ 1 Scan041 | |
| Letter from instrument makers Negretti & Zambra about supplying a larger 7' dial gauge. | 20th Feb 1923 | Box 40 \ 1 Scan042 | |
| Letter from Negretti & Zambra regarding a 0 to 350 lbs gauge and technical details of an Acrometer. | 21th Feb 1923 | Box 40 \ 1 Scan043 | |
| Letter from supplier Negretti & Zambra regarding the development of disc valves, Aerometers, and Manographs. | 21th Feb 1923 | Box 40 \ 1 Scan044 | |
| Obtaining a sample thermometer for motorcars from Messrs. Negretti & Zambra. | 3rd Mar 1923 | Box 40 \ 1 Scan045 | |
| Request to order two distance thermometers from Messrs. Negretti & Zambra, specifying one should be centigrade. | 26th Jun 1923 | Box 40 \ 1 Scan046 | |
| Letter from Negretti & Zambra regarding the price and specification of dial thermometers. | 6th Jul 1923 | Box 40 \ 1 Scan047 | |
| Letter to Negretti & Zambra detailing the specifications for a 5-inch dial thermometer instead of an 8-inch one. | 23th Jul 1923 | Box 40 \ 1 Scan048 | |
| Request to order one Distance Thermometer from Messrs. Negretti & Zambra with a modified gas connection. | 27th Jul 1923 | Box 40 \ 1 Scan049 | |
| Letter to Messrs. Negretti & Zambra chasing the delivery of a Distance Thermometer. | 3rd Sep 1923 | Box 40 \ 1 Scan050 | |
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