(14) W. M. S. asks how to make liquid glue. A. Take a wide mouthed bottle, and dissolve in it 8 ounces best glue in ½ pint water, by setting it in a vessel of water, and heating until dissolved. Then add slowly 2½ ounces strong nitric acid 36° Baume, stirring all the while. Effervescence takes place, with generation of fumes. When all the acid has been added, the liquid is allowed to cool. Keep it well corked, and it will be ready for use at any time. (15) E. H. F. asks what preparation steam laundries use to make their goods so stiff and have such a fine gloss, and how is it used, and, if used with starch, is hot or cold starch used? A. Melt 2½ pounds of the very best A 1 paraffine wax over a slow fire. When liquefied, remove from the fire and stir in 100 drops oil of citronella. Have a lot of round new pie tins, clean and nice; place them on a level table, coat them slightly with sweet oil, and pour about six tablespoonfuls of the enamel into each tin. The pan may be floated in water to cool the contents sufficiently to permit the mixture to be cut or stamped out with a tin cutter into small cakes about the size of a peppermint lozenge. Two of these cakes added to each pint of starch will cause the smoothing iron to impart the finest possible finish to muslin or linen, besides perfuming the clothes. (16) J. T. M., Jr., asks for a tempering liquid for tempering a flat coiled spring, ⅛ of an inch thick, 1½ inches wide, 20 feet long, without drawing the temper. A. You can get a spring temper in the hardening bath. Harden in water or oil and draw temper in an iron pan of linseed oil at boiling temperature. (17) C. E. H. writes: I have nearly 1,000 feet of out-door steam pipe carried in elevated wooden boxes. What is a good and cheap pipe covering to prevent loss of heat? A. Pulverized charcoal or sawdust makes a good cheap insulation for steam pipes. The boxes should be large enough to allow 2 inches clearance all around the pipe, the latter to be retained in position by cleats. Boxes should be tight enough to prevent circulation of air. Tar the outside to make weather proof. (18) B. L. asks: 1. Is there any method for removing rust stains from white cloth or linen? A. See the table in SCIENTIFIC AMERICAN SUPPLEMENT No. 158, for the "Removal of Stains and Grease Spots." 2. Is there any book showing how to work out chemical problems, and giving answer in the back of the book? A. Professor J. P. Cooke's "Chemical Problems and Reactions" can be sent you postpaid for $1. (19) D. B. wants a receipt for a dark cherry stain for a white pine floor. A. Use rain water 3 quarts, annatto 4 ounces; boil in a copper kettle till the annatto is dissolved, then put in a piece of potash the size of a walnut; keep it on the fire about half an hour longer, and it is ready to bottle for use.