and machines.  Sometimes 25, 30, 40 and even 50 per cent. of your power is consumed through lack of good oil.  When you buy a water wheel, be sure to buy one small enough to run at full gate while the stream is low during the summer months.  If you want more power than the small wheel will give, then put in two or more wheels of various sizes.  When it becomes necessary to trim a piece of rubber, it will be found that the knife will cut much more readily if dipped in water.  When forging a chisel or other cutting tool, never upset the end of the tool.  If necessary cut it off, but don’t try to force it back into a good cutting edge.  In tubular boilers the handholes should be often opened, and all collections removed from over the fire.  When boilers are fed in front, and are blown off through the same pipe, the collection of mud or sediment in the rear end should be often removed.  Nearly all smoke may be consumed without special apparatus, by attending with a little common sense to a few simple rules.  Suppose we have a battery of boilers, and “soft coal” is the fuel.  Go to the first boiler, shut the damper nearly up, and fire up one-half of the furnace, close the door, open damper, and go to the next boiler and repeat the firing.  By this method nearly, if not quite, all the smoke will be consumed.  A coiled spring inserted between engine and machinery is highly beneficial where extreme regularity of power is required.  It is well known that a steam engine, in order to govern itself, must run too fast and too slow in order to close or open its valves; hence an irregularity of power is unavoidable.

A “Paste” Metal Polish for Cleaning and Polishing Brass.—­Oxalic acid 1 part, iron peroxide 15 parts, powdered rottenstone 20 parts, palm oil 60 parts, petrolatum 4 parts.  See that solids are thoroughly pulverized and sifted, then add and thoroughly incorporate oil and petrolatum.

Cough Candy or Troches.—­Tincture of squills 2 ounces, camphorated tincture of opium and tincture of tolu of each 1/4 ounce, wine of ipecac 1/2 ounce, oil of gautheria 4 drops, sassafras 3 drops, and of anise seed oil 2 drops.  The above mixture is to be put into 5 pounds of candy which is just ready to take from the fire; continue the boiling a little longer, so as to form into sticks.

How to Oxidize Silver.—­For this purpose a pint of sulphide of potassium, made by intimately mixing and heating together 2 parts of thoroughly dried potash and 1 part of sulphur powder, is used.  Dissolve 2 to 3 drachms of this compound in 1-3/4 pints of water, and bring the liquid to a temperature of from 155 degrees to 175 degrees Fah., when it is ready for use.  Silver objects, previously freed from dust and grease with soda lye and thorough rinsing in water, plunged into this bath are instantly covered with an iridescent film of silver sulphide, which in a few seconds more becomes blue black.  The objects are then removed, rinsed off in plenty of fresh water, scratch brushed, and if necessary polished.