Show SAVING GOLD AND SILVER Electricity Extends 1 Helping JIand to the erA er-A French photographic journal describes a method of recovering the gold and silver waste of photographic processes by means of electricity The process consists of suspending sus-pending in the solutions containing these metals a plate of carbon to the positive pole of the battery and a zinc plate to the negative nega-tive the two being separated by the space of about an inch and a half With the closing of the circuit from any ordinary battery there is formed on the zinc electrode elec-trode a black deposit which falls to the bottom of the solution This deposit after being removed and dried is melted in a crucible forming an ingot of metal The Door Liehts the Room An efficient method of controlling the electric light current of hotel rooms has been devisedthe mechanism being attached Ito I-to the bolt on the door the opening or shutting shut-ting of tho door turning on or shutting off the current When the guest enters tho room the shooting of the bolt back closes a circuit and the lamps in the room are lighted When the person goes out the locking of the door from the outside breaks the circuit cir-cuit and the lights are extinguished As there is usually a second bolt in hotel rooms the locking of the door at night from the inside will not affect the burning of the lights New Tin Deposits in China I is reported that a large deposit of tin has been discovered opposite Hong Kong The attention of the owners was frat called to the deposit by the uncovering of the ore by the heavy rains of recent years It is said that the tin extends to a considerable consider-able depth many thousands of tons being procurable merely for the labor of removing remov-ing the surface ore |