Index of Inventions

1884 Scientific American  
The liquid opo<;leldoc is prepared by taking 2 ounces Castile soap shavinf(s, and diBsolving them in one quart alcohol, with gentle heat, then add 1 ounce camphor, � ounce oil rosemary, and 2 ounces spirits hartshorn (aqua ammonia) For cure of rheumatism, we advise conBuliation with physician. It is impossible to re commend any prescription without first seeing the patiem. (3) G. A. S. asks what he can use to remove varnish and paint from wood. A. We would recommend you to use a solnt.ion of
more » ... stic soda. lt is applied with a brush made of bri sties, and after a while is rinsed off with water. This operation is re peated several times, according to the thi ckness of the paint. Some caution is neceBsary to prevent the wood checkinf(. By this means the wood is restored to its natural color. (4) H . C. asks for any apparatns or dialyzer by whictJ alkali and silica in "olution (solution of silicate of soda) can be separated in large quantities, retaining the alkali in solution in one vessel and the silica in solution in another. A. We do not remember any mechanical apparatus by which the silica can be separated from the waterglass. Chemically, however, tbat is, by the addition of alkaline carbonates or chlorides, the silica will be thrown down. (5) M. M. W.-On page 2499 of SCIEN TIFIC AMERICAN SUPPLEMENT, No. 157, several recipes for indestructible inks are given, either of which will probably meet yonr demands. The majority of inks contain glycerine, the tendency of which is to prevent their perfect drying, and bence tbe blurring to which yon allude.
doi:10.1038/scientificamerican05031884-283 fatcat:73ykejmqdjgfliuifzamjgi6gy