This lamp is typical of lamps used in Welsh Coal Mines. It was purchased from the supplier around mid 1995. The Welsh Miners’ Lamps were ingeniously designed over 180 years ago to alert coal miners to danger. It ensures the burning of a protected flame in the presence of explosive gas, by regulating the necessary supply of atmospheric air, and by allowing the products of combustion to pass through without igniting the gaseous atmosphere. If the atmosphere is so heavily charged that noxious gas enters the lamp, its presence will be indicated by a change in the length and color of the flame, and (unless there are exceptional circumstances), the miner has sufficient warning to secure his safety. (http://www.welshminerslamps.com/info_lamp_personaluse.shtml, accessed 06/05/2015) E. Thomas & Williams, Ltd. mining lamps have been in continuous production since 1860. Cambrian Lamps are approved for use in coal mines where methan gas and oxygem deficinecy are hazards.Solid Brass traditional miners Flame Safety Lamp with Copper Chimney. The base of this lamp is tooled from solid brass because brass does not spark when it hits rock and is therefore the safest metal to use underground. The lamp burns lamp oil (kerosene). R. Thomas and Williams Ltd Makers Aberdare Wales Cambrian No 152897mining lamp, miner's lamp, thomas and williams, wales, welsh, welsh miners lamp, mining, cambrian lampworks, miners flame safety lamps

Louis Heinrici, Germany, circa 1900 a small Stirling type hot air engine in which a body of air is worked constantly, being alternately heated and cooled during each revolution of the crankshaft. Heinrici hot air engines are of the valveless, closed cycle type, generally called Stirling cycle engines, after Robert Stirling, the Scottish Presbyterian minister who pioneered their development in the early 1800's. They operate by alternately heating and cooling a quantity of air, called the working fluid, contained in the engine's internal spaces. Heat is applied externally and passes through the cylinder wall, heating the working fluid, which is then expanded against a piston to do mechanical work. After heating and expanding, the working fluid is moved to a cool space where it cools and contracts before being returned to the hot space for the cycle to repeat. It has a displacer (just a loose piston), below and in the same cylinder as the power piston to which it is connected via cranks and linkages so as to lead by 90degrees of crankshaft angle. The displacer space and the piston space are connected by the annular gap around the loose fitting displacer so that the working fluid moves between these spaces and changes volume by the appropriate ratio as the engine rotates. Because they have no valves and experience no sudden pressure changes, Stirling engines are noted for quietness and reliability. Heinricis use air at atmospheric pressure for their working fluid, but for higher specific output (power for size) and better efficiency, modern Stirling cycle engines use pressurised gas- air, nitrogen, helium or hydrogen.Historic - Hot Air Engine - MotorHot Air Motor made of Steel with two drive wheels. a small Stirling type hot air engine in which a body of air is worked constantly, being alternately heated and cooled during each revolution of the crankshaft. Heinrici Motorheinrici hot air motor, puffing billy

In 1905 Richard Squire was manager of the West Berry Consols at Allendale, and developed an improved system of mine ventilation, which was supported in "The Age."[4] He was successful in combating and remedying the gas and ventilation troubles of the Deep Mines of Creswick and Allendale Districts after all had failed.Hand written report on Cause of Gas or foul air innundating mines during periods of low atmospheric pressure.Royal commission stamp to right hand corner dated 22 Jun 1903richard squire, report, cause of gas or foul air innundating mines during periods of low atmospheric pressure, royal commission, ventilation and sanitation of mines

When Hewitt introduced his regulating stopcock in 1887, attempts were made to dilute the nitrous oxide with air and so obviate the element of asphyxiation. The method was to be seen in London, mainly in dentistry and minor surgery, so late as 1930. It was not very successful. To give even 10% of oxygen (which is not enough) the gas-mixture must contain 55% of air and 45% of nitrous oxide. The latter is thus so diluted by atmospheric nitrogen as to be incapable of producing anaesthesia except by asphyxiation. "Gas-air" was confined to analgesia, for example in midwifery. (Source: Penn catalogue)Brown leather facemask attached to metal inhaler and stopcock device that has been sectioned to reveal its inner workings. The various exposed channels have been painted either green, red, blue or purple.Engraved into side of stopcock: HEWITT'S / N20-02 / 1895 / G. Kaye sect. 1952. •Stamped into other side of stopcock: [indecipherable] BARTH & CO. / SOLE MAKERS / 54. POLAND STREET LONDON.W.frederic hewitt, stopcock, nitrous oxide, oxygen, gas-air