One of the most enjoyable things about researching Nicholson’s numerous interests and activities is the way that it has brought me into contact with so many people that I might never encountered otherwise. Experts in a variety of fields have been unbelievably kind and generous in sparing their time and energy to help me understand what Nicholson was up to and the context of his work at the time. One thing they all share has been a keenness to see that William Nicholson and his achievements should be better known and appreciated.
The most recent example is horological guru Jonathan Betts - Curator Emeritus at the Royal Observatory (National Maritime Museum), Greenwich, a horological scholar and author, and an expert on the first marine timekeepers created by John Harrison in the middle of the 18th century.
Jonathan is also the librarian to the Antiquarian Horological Society, and recently authored two articles about Nicholson which have been published in the society’s journal
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In 1806) and then in 2013 he acquired a collection of horological papers which had been published by Nicholson. A little while after this, I must have popped into his in-box after finding his paper on Nicholson’s good friend John Hyacinth Magellan (1722-1790).
In this article, Jonathan Betts forensically examines the two clocks which have been signed by Nicholson, although – as we know that Nicholson employed instrument-makers – ‘it seems very likely that Nicholson oversaw the clock’s construction to his specification’ rather than having any ‘hands-on’ involvement,
Nicholson’s table regulator clock lives at the British Museum (and was highlighted in an earlier blog). Betts describes the design and combination of features in the movement of this clock as “unique” and “evidently designed so that the technical features can be exposed and appreciated – very much in line with Nicholson’s desire to disseminate technical information”.
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The second clock - featuring for the first time in public in the AHS Journal - is described as a ‘miniature gimballed regulator” with parts dated 1805 and 1806, and as “more elegant” and “even more exposed and ‘on show’”.
Unfortunately, Betts describes how this design had a ‘significant failing in the proportions of the dead-beat escapement’ which can lead to a stopping or bottoming, although this may have been prevented by the gimbal arrangement in the design.
A gimbal is a pivoted support that permits rotation of an object about an axis (for example, like a stabiliser on a hand-held camera), and it seems that this clock was ‘almost certainly mounted on a tripod and was thus intended to be used in a ‘portable’ environment’ for example, at sea or when surveying.
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If you are interested in horology and the technical details of these two clocks, then it is possible to purchase a single issue of
Edited by Desmond King-Hele, Letter 86-6 from Erasmus Darwin to Josiah Wedgwood, 21 April 1786, starts off “Sir, Mr Nicholson is an ingenious and accurate man …” and continues a series of discussions between the men about oil lamp designs, leading to the comment that “The pyramidical lamp would be more pleasing to they eye than the concentric one of Mr Nicholson.”
Having been searching for Nicholson’s 'concentric lamp' for many years, I was delighted to finally track it down in The London Magazine, of May 1785:
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As the attention of the world has been much excited by the powerful effects of Argand’s Lamp, and as there are many who are desirous of making use of it provided its advantages were clearly ascertained, I presume the following description of the instrument and its effects will not be unacceptable to the public.
The apparatus consists of two principal parts, a fountain to contain the oil, and the lamp itself. Of the former it is unnecessary to speak: the lamp is constructed as follows. The external parts consist of an upright metallic tube one inch and six-tenths in diameter, and three inches and a half in length, open at both ends. Within and concentric to this is fixed another tube of about one inch in diameter, and nearly of equal length; the space between these two tubes being left clear for the passage of air. The interior tube is closed at the bottom, and contains another similar tube a little more than half an inch in diameter. The third tube is soldered to the bottom of the second. It is perforated throughout so as to admit a current of air to pass through it, and the space between this tube and that which invirons it contains the oil. An ingenious apparatus, containing a piece of cotton cloth whose longitudinal threads are much the thickest, is adapted to nearly fill the space into which the oil flows. It is so contrived that the wick may be raised or depressed at pleasure. When the wick is considerably raised it is seen of a tubular form, and by the situation of the tubes already described is accessible to the air, both by means of the central perforation and the space between the exterior and second tube. When the wick is lighted, the flame is consequently in the form of a hollow cylinder, and is exceedingly brilliant. It is rendered somewhat more bright, and perfectly steady, by adapting a glass chimney whose dimensions are nearly the same with that of the exterior tube first described.
I hope this short description will be sufficient to convey an adequate idea of the instrument and shall therefore proceed to mention its effects. If the central hole be stopped, the flame changes from a cylindrical to a pyramidical form, becomes much less bright, and emits a considerable quantity of smoke. If the whole aperture be entirely or nearly stopped and the combustion becomes still more imperfect. The access of air to the external and internal surfaces of the flame is of so much importance, that a sensible difference is perceived when the hand or any other flat substance is held even at the distance of an inch from the lower aperture. There is a certain length of wick at which the effect of the lamp is the best. If the wick be too much depressed, the flame, though white and brilliant, is short; if it be raised, the flame becomes longer, and consequently the light more intense and vivid. A greater increase of the length, increases the quantity of the light, but at the same time the upper part of the flame assumes a brown hue, and smoke is emitted.
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The lamp was filled with oil and weighed, it was then lighted and suffered to burn so as to produce the greatest quantity of light without smoke. After burning one hour and fifty-two minutes, it was extinguished and found to have lost 589 grains of its weight. Now a pint of oil weights 6520 grains and costs sixpence three farthings in retail; the lamp therefore consumes oil to the value of one penny in three hours. It remains to be shewn at what rate per hour the same quantity of light might be obtained from the tallow candles commonly used in families.
The candle called a middling fix, weighing upon an average the sixth part of a pound of avoirdupois, is 10¾ inches long, and 2 inches and 6/10 inch circumference. I have chosen to make my comparison with this candle as being, I imagine, most commonly used. It is to be understood that the lamp gave its maximum light without smoke.
The best method of comparing two lights with each other, that I know of, is this: Place the greater light at a considerable distance from a white paper, the less light may be moved nearer or father from the paper, accordingly as the experiment requires. If now an angular body, as the most convenient figure, be held before the paper it will project two shadows, these two shadows can coincide only in part, and their angular extremities will in all positions but one be at some distance from each other: the shadows being made to coincide in a certain part of their magnitude, they will be bordered with a lighter shadow, occasioned by the exclusion of the light from each of the two luminous bodies respectively. These lighter shadows in fact are spaces of the white paper illuminated by the different luminous bodies, and may with the greatest ease be compared together, because at a certain point they actually touch one another. If the space illuminated by the less light appear brightest, that light is to be removed farther off; and on the contrary, if it be the most obscure, that light must be brought nearer the paper. A considerable degree of precision may be obtained by this method of judging of lights, and by this method the following comparisons were made.
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The candle was suffered to burn till it wanted snuffing so much, that large lumps of coaly matter were formed on the upper part of the wick. The candle then at the distance of 24 inches gave a light equal to that of the lamp at the distance of 129 inches: from this experiment
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