FOLIATING of GLOBE looking-glasses, is done as follows:
lows: Take five ounces of quicksilver and one ounce of bismuth; of lead and tin, half an ounce each: first put the lead and tin into fusion, then put in the bismuth; and when you perceive that in fusion too, let it stand till it is almost cold, and pour the quicksilver into it: after this, take the glass globe, which must be very clean, and the inside free from dust: make a paper funnel, which put into the hole of the globe, as near the glass as you can, so that the amalgam, when you pour it in, may not splash, and cause the glass to be full of spots; pour it in gently, and move it about, so that the amalgam may touch everywhere: if you find the amalgam begin to be curdly and fixed, then hold it over a gentle fire, and it will easily flow again; and if you find the amalgam too thin, add a little more lead, tin, and bismuth to it. The finer and clearer your globe is, the better will the looking glass be.
Dr Shaw observes, that this operation has considerable advantages, as being performable in the cold; and that it is not attended with the danger of poisonous fumes from arsenic, or other unwholesome matters, usually employed for this purpose: besides, how far it is applicable to the more commodious foliating of the common looking glasses, and other speculums, he thinks, may deserve to be considered.