A correspondent writing to us from Seneca Falls, N. Y., states, that the best proportions of alcohol and camphene, for making the above fluid, are, one of fresh camphene to four of 95 per cent. alcohol, by measure. " If these materials are good," he says, " a perfect combination in these proportions will be effected, and the mixture will be quite transparent." We have always given the proportions of one of camphene to nine of alcohol, because it frequently happens, that the camphene contains a little resin in excess, and therefore requires more alcohol. The purer the alcohol, the more camphene will be taken up by it, and a better fluid produced. Three parts of pure alcohol (which is seldom to be obtained however) will take up one part of camphene, and make a very superior fluid to that in general usc.