Page:Pyrotechnics the history and art of firework making (1922).djvu/239

 in spite of or perhaps because of his lack of chemical knowledge, he was able to produce a work which, from the point of view of the practical pyrotechnist, has never been equalled.

His researches were conducted by practical experiments; he had one end in view, namely, pyrotechnic effect, and by exhaustive trials of the materials obtainable, unbiased by theoretical consideration, he succeeded in advancing the art to a stage undreamed of a few years previously. It is true that many of his formulæ are not in use to-day, in this country that is, on account of the danger of using sulphur or sulphur compounds in conjunction with chlorate of potash; but there can be no doubt that his writings and research work laid the foundation of modern pyrotechnic practice.

Once the theory of colour production was established, that is to say the volatilisation of a metal salt in a hotly burning composition, it was a matter of less difficulty to either eliminate the sulphur, which was present chiefly as a burnable, or to replace it.

This prohibition, as we have seen, took place in 1894, under Order in Council 15, and affected the production of coloured fireworks far less than might have been anticipated. During the period between the introduction of chlorate of potash and the Order in question, the development of commercial chemistry had increased greatly the number of chemicals available in pyrotechny, so that in some few cases it was found possible to replace the chlorate.

In addition, moreover, most of the leading makers, anticipating some form of restriction on this admixture, had been for some time previously seeking substitute colour formulæ, and although it may be said by some that colours were obtained by the use of chlorate and sulphur which have not been equalled by subsequent formulæ, yet most have not only been equalled but improved upon, and the small minority