Another American of note, Benjamin Thompson, better known as Count Rumford (q.v.), in 1789 wrote an exhaustive essay on 'The Management of Light in Illumination? He constructed over 100 different lamps in his extended experiments. He photom eter to measure the relative intensity of light emitted by different illuminants. He found that the purest white light could be obtained by means of lamps properly constructed, using clarified vegetable or animal oil, at less than one-eighth of the cost for the same degree of light produced by wax candles, and for about half the cost of tallow candles. He invented but one burner. In this he constructed a cen tre, flat wick tube, with two similarly shaped tubes placed at acute angles on either side of the wick tube, his design being to supply oxygen through the angular tubes impinging on the wick tube. This burner did not satisfy him, and its introduction did not become general. In his further experiments he confined himself to the Argand burner, and devoted his attention to the better construction of the lamp proper. His aim was to produce a lamp in which the shadow should be eliminated as much as pos sible. He invented what was known as the ((Astral lamp,) which consisted of constructing the oil reservoir in the form of a flat, circular tube with radiating arms attached to the pedes tal of the lamp, and securing the burner within the circle. He also introduced what he called the Illuminator?) This was for use in halls, ballrooms and salons. He also made what he called a ((Dining-room and also a table or reading illuminator. All of Count Rumford's investigations and his ex tended experiments relating to lights and lamps, were carried on while he was in the public service of the Elector of Bavaria, who created him a count as a reward for his valuable ser vices and as a recognition of his great learning and the importance of his researches and inventions.
Hundreds of patents have been granted to American inventors for lamps and lamp burn ers. One of the earliest patents on record in the United States Patent Office was for a de vice in which an adaptation was made of Frank lin's two-wick tubes by securing them to a per forated disc through which the tubes passed. Beneath the disc was a cork through which the tubes also passed, the cork being cemented to the under side of the disc. This could then be fitted into the top of the lamp the same as a cork fits the neck of a bottle. This was mostly applied to glass lamps, which were first intro duced in America in 1810. In 1812 one J. Neal secured a patent for a lamp provided with a telescopic sliding cylinder, the wick tubes were secured to the top of the cylinder, being screwed into a collar which formed the upper part of the tube. When the lamp was filled with oil, a float on the bottom of the tube extended the cylinder to its full length. The wicks were long, reaching to the bottom of the cylinder. As the oil was consumed the cylinder was cor respondingly lowered, thus keeping the wicks uniformly submerged in the oil as long as any remained in the lamp. These lamps were made
in tin brass and pewter and became quite popu lar. In 1839 one J. Price of Nashville, Tenn., obtained a patent on an arrangement for burn ing pine knots. According to the directions the knots were to be cut up into small pieces and inserted into a tube, which had a diameter of about an inch and a half and a base not unlike an ordinary brass candlestick. A spring inside the upright tube was compressed as the pieces of pine knots were forced in. When the tube had been filled an oval cap or cover with a large opening was placed over the top and secured by a bayonet clutch. The spring forced up the wood to be burned through the opening in the cap; as it was burned away the ash fell into a circular receptacle secured on the up right pedestal. A sheet iron chimney with a broad hood partly surrounding the flame was provided as the specification says to convey the ascending smoke away from the face of the person using the lamp) P. S. Moorhouse ob tained a patent in 1830 for a lighting device in which balls of cotton or tow saturated with grease or. fat were burned while held by an up right supporting claw secured to a pan base, in which the ash was collected. Between 1843 and 1845 S. Rust secured eight patents on lamps and five on burners. These patents did not in troduce any new features, and consisted mostly of the introduction of novelties relating to forms and supposed ornamentation. His inven tions in the line of burners did not involve any new features and possessed but little real utility.
The so-called Lamps,' patented in 1843 by the Philadelphia firm of Cornelius & Company; were a great improvement over any table lamp so far introduced. They were con structed to burn lard oil. The burner 'proper was a modification of Argand's. The wick tube, over which the circular wick closely fitted, ex tended through the bottom of the oil reservoir, where it was provided with openings for the admission of air. The heat conveyed through the lard oil by the wick tube served to keep the oil in a liquid state in cold weather. The burner was so constructed that the flame was diffused more generally than in other lamps, while the bulb-shaped glass chimney created a hot-air chamber in which all free carbon was consumed. The light was profuse, white and clear. This firm manufactured a large variety of elegant lamps, which were used extensively in the homes of the wealthy. Benkler's lamp, intro duced in 1840, had a tube through which air was admitted to the flame, the angle of the tube being such that an upward movement of air was produced when the oxygen came in con tact with the heat, and thus a forced draught was secured which made the light constant and aided greatly in the consumption of smoke. Through the means thus adopted cheap heavy oils could be burned without the offensive smell and excessive smoke produced by cheaper lamps when these low-grade oils were consumed.