The age-herald., 1897-10-10
! NOTES ON SCIENCE AND INDUSTRY. s
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Those interested in mining are inves- hgatang a new cyanide process invented by pr. Keith, formerly OF San Francisco, now of London, dn which during the dis solving lfe adds to the solution of potas- Eium cyanide eertai amount of cyanide of mercury, the best results being ob- tained wlen the solvelult con.afns 0.5 per cent. of potassium cyanide and 0025 per cent. cyanide of mercury. This mixture of the cyan1des, it is claimed, operates more speedy than the simple potassium cyanide. For Line recovery of the gold from this solution tho process is an eleotrolytfc one. The gold and the mer- cury are deposited together upon amal- gamaIted copper plates, the analgam so deposited is scraped off, and the gold recovered by distlfllng off the mercury tin the usual way. The anode is not al- lowed ito dip in the cyanide solution, but it is placed in @ separate compartment and surrounded with a solution of arnal- kaline Eabt, and in this way the cyanide does met become deleemposed. The elec- tro-motiDe force of rthe current need mot be more tlhan half a volt, and the current density of the depositing surface may be as low as 0.06 an1pere per square foot.
 The driving of light carriages by means of hquefied caIbcnic acid as mo- Hive power has been oftsn proposed, rthe difficulty chiefly encountered being the great absorption of heat, and consequent 1y loss of efficiency through the refrig- eration of the engine as dhe liquid ex pands and returns to the gaseous state. The latest method brought forward for | fx, to in genulty of a French inventor, M. Rassi- dnier, his method being to press the car boric acid through capillary tubes in @ chamber heated to PAS degrees F. by pe- troleum or coal briquettes, the heated gas being then admitted to the engine cylinder, where it acts upon the piston, and is then led into a chamber or jacket surrounding the Hquefied gas. The g'ase- ous acid giving up the necessary heat to change the liquid acid to the gaseous form of 30 degrees C., pressure of 70 atmosphereS Is finally developed. The final exhaust of the gas takes place from the jacket or chamber. The state ment, is in substance, that the capillary heater insures the first expansion of the gas, while the addition of pressure through the heating of the reservoir by the exhaust gas takes place only when the engine is working.
 The various experiments made with Sopar engines by the French in Algeria, where the sun shines at all times and with great power, have been attended in some instances with marked success The best apparatus is stated to be a sir1l- pie arrangement of boiler and concave mdrror, the steam genenated being con- densed in a coifed tube surrounded by water. this being intended for distilling water merely. But in India an inventor named Adams has contrived some ma- chimes by which more varied results are accomplished. One of these is what is termed a cooking box, made of wood and lined with refiecting mirrors, at the bottom of the box being a small copper boilers covered with glass to retain the heat of the rays concentrated by mirrors upon the boiler. In this contrfvance any sort of food may be quickly cooked, the result being stew or boil if the steam is retained, or if allowed to escape 1t is g. bake. The heat with this device may be augmented fndef- nftely by increasing the diameter of the box.
 The committee of the American Boiler makers association on standard specif- cations recommends an es'ta bished dis finction hereafter between shell steel and hange steel According to the new rule shell steel nioli exposed to the direct aheat of the fire or gases of combustion may have from 65,O00 to 75,0OO pounds tensile strength, with am elastic limit of