| Description | Date | Identifier | |
| Instruction to the Works to use 16/18 volt bulbs on the warning light. | 10th Jan 1928 | Box 175 \ 4 img108 | |
| Radiator thermometer contact failures being resolved by using 16 Volt bulbs. | 5th Jul 1928 | Box 175 \ 4 img109 | |
| Query regarding whether radiator thermometers on production are fitted with a top stop. | 5th Jul 1928 | Box 175 \ 4 img110 | |
| Faulty Cambridge thermometer and the arrangement to have a stop fitted free of charge. | 14th Jul 1928 | Box 175 \ 4 img111 | |
| Order for a radiator warning lamp for a 14-G4 dashboard, specifying it should be equipped with green glass. | 22th Oct 1928 | Box 175 \ 4 img112 | |
| Availability of warning lights from Central Stores stock. | 21th Dec 1928 | Box 175 \ 4 img113 | |
| The failure and replacement of a Cambridge Radiator Thermometer due to burnt contacts. | 27th Aug 1929 | Box 175 \ 4 img114 | |
| Request to order three special transmitting thermometers with warning lights from the Cambridge Scientific Instrument Co. | 28th Apr 1930 | Box 175 \ 4 img115 | |
| The correct temperature setting for radiator thermometers. | 16th Jun 1930 | Box 175 \ 4 img116 | |
| Alteration No. 148 for the Transmitting Water Thermometer, approving its use and requesting modifications for civil aircraft. | 16th Feb 1931 | Box 175 \ 4 img117 | |
| Air Ministry letter regarding the approval of a Transmitting Water Thermometer, Alteration No.148. | 12th Feb 1931 | Box 175 \ 4 img118 | |
| Letter to Cambridge Scientific Instrument Co. Ltd. requesting a quotation for thermometers and a bridge for radiator cooling experiments. | 13th Mar 1931 | Box 175 \ 4 img119 | |
| Circuit diagram for a bridge for resistance thermometers. | 14th Mar 1931 | Box 175 \ 4 img120 | |
| Letter from Cambridge Instrument Company discussing methods for measuring radiator water temperature. | 14th Mar 1931 | Box 175 \ 4 img121 | |
| Letter from Cambridge Instrument Company regarding thermocouple instruments and a proposed visit. | 17th Apr 1931 | Box 175 \ 4 img122 | |
| Letter to The Cambridge Instrument Co. requesting an estimate for resistance thermometers to measure radiator temperatures. | 17th Apr 1931 | Box 175 \ 4 img123 | |
| Letter from Cambridge Instrument Company regarding specifications and cost for a radiator temperature outfit. | 22th Apr 1931 | Box 175 \ 4 img124 | |
| Letter to Cambridge Instrument Co. confirming the required specifications for a measuring bridge. | 23th Apr 1931 | Box 175 \ 4 img125 | |
| Letter confirming a change in specification for a bridge instrument's temperature range. | 27th Apr 1931 | Box 175 \ 4 img126 | |
| Letter from the Cambridge Instrument Company providing a quotation for temperature measuring apparatus. | 12th May 1931 | Box 175 \ 4 img127 | |
| Quotation from Cambridge Instrument Company Ltd. for a special temperature measuring unit and resistance thermometers. | 12th May 1931 | Box 175 \ 4 img128 | |
| Blueprint of an instrument panel featuring thermometer terminals and range selecting sockets. | 1st May 1931 | Box 175 \ 4 img129 | |
| Blueprint for a special full-size thermometer selecting switch and temperature gauge. | 1st May 1931 | Box 175 \ 4 img130 | |
| Blueprint of a resistance plug and a rheostat dial divided into degrees. | 1st May 1931 | Box 175 \ 4 img131 | |
| Blueprint for a testing outfit featuring a graduated dial. | 1st May 1931 | Box 175 \ 4 img132 | |
| Blueprint for a B.P Teak Case. | 9th May 1931 | Box 175 \ 4 img133 | |
| Blueprint for a B.P. Teak Case. | 9th May 1931 | Box 175 \ 4 img134 | |
| Letter from Cambridge Instrument Company offering a Torsional Accelerometer on a seven-day sale or return basis. | 23th Jun 1931 | Box 175 \ 4 img135 | |
| Quotation from Cambridge Instrument Company, Ltd. for a rotational accelerometer and other instruments. | 24th Jun 1931 | Box 175 \ 4 img136 | |
| Inquiry to The Cambridge Instrument Co. about hiring a recording rotational accelerometer for torsional vibration tests. | 25th Jun 1931 | Box 175 \ 4 img137 | |
| Letter from the Cambridge Instrument Company regarding an enquiry for a Torsional Vibration Recorder. | 26th Jun 1931 | Box 175 \ 4 img138 | |
| Letter declining a request to hire a Rotational Accelerometer, offering to sell one instead. | 30th Jun 1931 | Box 175 \ 4 img139 | |
| Quotation from Cambridge Instrument Company, Ltd. for a rotational accelerometer and other scientific equipment. | 30th Jun 1931 | Box 175 \ 4 img140 | |
| Requesting an order for two Cambridge high reading thermometers for urgent evaporative cooling tests on the Meccano hangar. | 3rd Aug 1931 | Box 175 \ 4 img141 | |
| Confirming a Cambridge thermometer for a 20-EX is being returned to the makers for a new dial. | 2nd Jun 1932 | Box 175 \ 4 img142 | |
| Test comparing the effect of altitude-related air pressure on Cambridge and Negretti & Zambra thermometers. | 20th May 1933 | Box 175 \ 4 img143 | |
| Graph showing the effect of altitude (20,000 ft) on the gauge reading of a Cambridge Ether Thermometer. | 1st May 1933 | Box 175 \ 4 img144 | |
| Faulty Smith radiator thermometer being sent for repair and a request for a failure report. | 8th Aug 1933 | Box 175 \ 4 img145 | |
| Instructing the supply of bi-metal thermometers and a steam valve, with A.I.D. inspection required before dispatch. | 6th Oct 1933 | Box 175 \ 4 img146 | |
| Order request for pyrometers and compensating cable for a Centricast Bearing Rig. | 20th Oct 1933 | Box 175 \ 4 img147 | |
| Enquiry to The Cambridge Instrument Co. about the capabilities of their rotational accelerometer for measuring crankshaft vibrations. | 23th Oct 1933 | Box 175 \ 4 img148 | |
| Letter from Cambridge Instrument Company regarding their rotational accelerometer, its function as a vibrograph, and recent improvements. | 24th Oct 1933 | Box 175 \ 4 img149 | |
| Letter from Cambridge Instrument Company describing the features and sensitivity ranges of an instrument and an enclosed photo of a new projector. | 25th Oct 1933 | Box 175 \ 4 img150 | |
| Letter from Cambridge Instrument Company Ltd. providing a quotation for a Rotational Accelerometer and associated equipment. | 25th Oct 1933 | Box 175 \ 4 img151 | |
| Quotation from Cambridge Instrument Company Ltd. for a Rotational Accelerometer, Contact Maker, and Portable Viewer. | 25th Oct 1933 | Box 175 \ 4 img152 | |
| Letter from Cambridge Instrument Company regarding the suitability and pricing of different thermometers for a test car. | 27th Oct 1931 | Box 175 \ 4 img153 | |
| Photograph of a Cambridge thermometer gauge face measuring from 0 to 50 degrees Celsius. | 5th Nov 1931 | Box 175 \ 4 img154 | |
| Follow-up letter from Cambridge Instrument Company regarding a thermometer for a test car. | 5th Nov 1931 | Box 175 \ 4 img155 | |
| Letter from Cambridge Instrument Company offering alternative thermometers and pricing for a test car. | 27th Oct 1931 | Box 175 \ 4 img156 | |
| Letter to The Cambridge Instrument Co. Ltd. regarding the specifications of a rotational accelerometer and arranging a demonstration. | 8th Nov 1933 | Box 175 \ 4 img157 | |
| Letter from Cambridge Instrument Company clarifying the use of their Vibrograph for measuring crankshaft vibrations. | 10th Nov 1933 | Box 175 \ 4 img158 | |
| Letter from Cambridge Instrument Company detailing how to connect an instrument and the terms for a demonstration or trial. | 12th Nov 1931 | Box 175 \ 4 img159 | |
| Letter to The Cambridge Instrument Co. Ltd. confirming a thermometer has been obtained. | 12th Nov 1931 | Box 175 \ 4 img160 | |
| Letter to The Cambridge Instrument Co. Ltd. rejecting their belt-driven rotational accelerometer. | 13th Nov 1933 | Box 175 \ 4 img161 | |
| Letter from Cambridge Instrument Company regarding the suitability and supply terms of a Rotational Accelerometer. | 17th Nov 1933 | Box 175 \ 4 img162 | |
| Letter from Cambridge Instrument Company Ltd. regarding a trial period for an instrument to measure torsional vibrations. | 17th Nov 1933 | Box 175 \ 4 img163 | |
| Enquiry for particulars about a Cambridge Exhaust Gas Analyser. | 1st Oct 1932 | Box 175 \ 4 img164 | |
| Request to arrange a replacement thermometer for a Bentley chassis due to a fractured pipeline. | 26th Jul 1934 | Box 175 \ 4 img165 | |
| Return of a Smith Thermometer from chassis 4.B.IV for recalibration. | 7th Sep 1934 | Box 175 \ 4 img166 | |
| The purchase of a Cambridge dial thermometer for a new electric drying oven. | 1st May 1935 | Box 175 \ 4 img167 | |
| Letter from S. Smith & Sons following up on the receipt of a failed thermometer for concave dial instruments. | 27th May 1935 | Box 175 \ 4 img168 | |
| Letter to S.S. Smith & Sons regarding the failure and return of concave dial instruments. | 12th Jun 1935 | Box 175 \ 4 img169 | |
| Request to exchange a faulty Cambridge Dial Thermometer which is reading low because the bulb does not fit correctly in the chamber. | 1st Jun 1935 | Box 175 \ 4 img170 | |
| Letter from S. Smith & Sons (Motor Accessories) Ltd acknowledging a letter regarding a Concave Dial Thermometer and a defective Oil Gauge. | 13th Jun 1935 | Box 175 \ 4 img171 | |
| Order to despatch a Cambridge pattern 'A' thermometer to the Cambridge Instrument Co. Ltd. for modification. | 17th Oct 1935 | Box 175 \ 4 img172 | |
| Return of a failed Smith concave dial thermometer for repair. | 22th Oct 1935 | Box 175 \ 4 img173 | |
| Letter to S. Smith & Sons, Ltd. regarding experiments with flexible capillary tubes and a Negretti & Zambra altimeter. | 3rd Mar 1936 | Box 175 \ 4 img174 | |
| Letter to Messrs. Smith & Sons regarding a scheme to sound-insulate a car transmitting thermometer. | 5th Mar 1936 | Box 175 \ 4 img175 | |
| Letter from S. Smith & Sons acknowledging receipt of a letter regarding a transmitting thermometer. | 7th Mar 1936 | Box 175 \ 4 img176 | |
| Letter from S. Smith & Sons discussing the difficulty in sourcing thinner, more flexible capillary tubing for thermometers. | 7th Mar 1936 | Box 175 \ 4 img177 | |
| Letter from S. Smith & Sons regarding a thermometer bulb and an enclosed drawing. | 13th Mar 1936 | Box 175 \ 4 img178 | |
| Official order be sent to Messrs. Smith & Co. for a standard Ph.III type water thermometer. | 24th Mar 1936 | Box 175 \ 4 img179 | |
| Letter to S. Smith & Sons Ltd. regarding the suitability of a thermometer bulb and placing an order. | 24th Mar 1936 | Box 175 \ 4 img180 | |
| Letter from S. Smith & Sons acknowledging an order for a set of special parts with a thermometer for the Phantom III. | 27th Mar 1936 | Box 175 \ 4 img181 | |
| Letter to S. Smith & Sons Ltd. requesting the delivery of a special Ph.III Thermometer. | 7th Apr 1936 | Box 175 \ 4 img182 | |
| Letter from S. Smith & Sons confirming a special Phantom III Thermometer is ready for testing and despatch. | 8th Apr 1936 | Box 175 \ 4 img183 | |
| Insulated thermometer for the Phantom III, focusing on noise reduction using a rubber-insulated bulb. | 9th Apr 1936 | Box 175 \ 4 img184 | |
| Request for a report on the experimental silent thermometer and its design scheme for standardisation. | 10th Jun 1936 | Box 175 \ 4 img185 | |
| Schemes tested to prevent noise transmission through the dashboard thermometer. | 13th Jun 1936 | Box 175 \ 4 img186 | |
| Report comparing two design schemes for gland packing, detailing issues with scheme LeC.5060 and proposing modifications. | 13th Jun 1936 | Box 175 \ 4 img187 | |
| Letter to S. Smith & Sons requesting a quotation for thermometers with flexible capillary tubing for experimental work. | 24th Jun 1936 | Box 175 \ 4 img188 | |
| The standardisation of a rubber-mounted thermometer. | 24th Jun 1936 | Box 175 \ 4 img189 | |
| Letter from S. Smith & Sons (Motor Accessories) Ltd regarding an enquiry for a flexible capillary. | 25th Jun 1936 | Box 175 \ 4 img190 | |
| Requesting an urgent order for six Negretti and Zambra transmitting thermometers for the Aero beds. | 26th Jun 1936 | Box 175 \ 4 img191 | |
| Letter from S. Smith & Sons clarifying the required range for a thermometer dial. | 26th Jun 1936 | Box 175 \ 4 img192 | |
| Letter of inquiry to H.M. Hobson Components Ltd. regarding a new 'Telegage' water temperature gauge. | 26th Jun 1936 | Box 175 \ 4 img193 | |
| Letter to S. Smith & Sons Ltd. confirming receipt of their letter and specifying temperature ranges. | 27th Jun 1936 | Box 175 \ 4 img194 | |
| Letter from H.M. Hobson Components Ltd. regarding an enquiry for a K-S distant reading Telegage. | 30th Jun 1936 | Box 175 \ 4 img195 | |
| Page 2 of a letter from H.M. Hobson Components Ltd. regarding maximum instrument pressures and offering samples on loan. | 30th Jun 1936 | Box 175 \ 4 img196 | |
| Letter from S. Smith & Sons regarding the unsuitability of their standard thermometers and forwarding the request to their aircraft department. | 30th Jun 1936 | Box 175 \ 4 img197 | |
| Letter from Smiths Aircraft Instruments quoting for a Mercury-in-Steel type Oil Temperature Thermometer. | 1st Jul 1936 | Box 175 \ 4 img198 | |
| Letter requesting a sample water temperature recording instrument for testing and a price quotation. | 2nd Jul 1936 | Box 175 \ 4 img199 | |
| Letter from H.M. Hobson Components Ltd. regarding a query for a Hobson K-S Heat Indicator for experimental purposes and a price quotation. | 3rd Jul 1936 | Box 175 \ 4 img200 | |
| Letter from H.M. Hobson Components Ltd. regarding the dispatch of a Heat Indicator. | 10th Jul 1936 | Box 175 \ 4 img201 | |
| Letter from H.M. Hobson Components Ltd. regarding a visit to assist with the installation of a loaned Heat Indicator. | 14th Jul 1936 | Box 175 \ 4 img202 | |
| Telegram advising that Mr. Steadman is on holiday for two weeks. | 15th Jul 1936 | Box 175 \ 4 img203 | |
| Cover letter to H.G. Reigate Esq. forwarding a copy of a letter sent to Messrs. H.M. Hobson. | 15th Jul 1936 | Box 175 \ 4 img204 | |
| Letter to H.M. Hobson Components Ltd. regarding an employee's holiday and a visit from Mr. Reigate. | 15th Jul 1936 | Box 175 \ 4 img205 | |
| Letter from H.M. Hobson Components Ltd. acknowledging correspondence and arranging a future meeting after Mr. Steadman returns from holiday. | 16th Jul 1936 | Box 175 \ 4 img206 | |
| Letter to H.M. Hobson Components Ltd. arranging a discussion about a loaned heat indicator. | 27th Jul 1936 | Box 175 \ 4 img207 | |
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