The Press., 1904-06-15
DELEGATE BALANCES.
SCALES THAT WILL MEASURE THE
 WEIGHT OF A SIGNATURE.

Act OF the Sensitive Mechanism.
 Accuracy of Their Weights.
 So sensitive are the modern chem ists' and jewellers balances that not merely can they weigh accurately a quarter inch long human hair, but re- cord as well the differences in weight between any number of such pieces taken from the heads of different per- sons. And so absolutely correct are these scales that the same samples of hair weighed on a number of balances will show identical differences.
 With a balance of this sort it is possi- ble to weigh the infinitesimal quantity of ink required to write your sigma ture. All that is necessary Is to weigh the piece of blank paper, then to write your name on 1t and to weigh the pa- per again, taking the difference be- tween the two weights as that of the ink.
 Down in Maiden lane, in the great jewel district, scale expert was talk ing of these things the other day Within glass fronted closets lining his office were scores upon scores of bal ances. inclosed in glass and mahogany framed cases. ..... .,
 "Delicate?" said the expert, repeat ing a question. We have jewellers scales here that will weigh 500 carats of diamonds and will remain sensitive to the incOnceivably slight weight of one fve-hundredths of carat The moisture of your breath against one of the pans of this scale would throw it out of adjustment Touching one end of the beam with finger tip for ten seconds is enough to lengthen the beam. 1t would expand under the warmth of the hand sufh hciently to throw the needle pointer off the center.
 But, from an experts viewpoint, these scales are not the most remarka- ble. It is easy enough to make light scale sensitive beyond all requirements of practical purposes. It is when we turn out scale that can weigh heavier loads and still remain sensi- tive that we feel we have accomplish ed something. Here, for instance, is a scale that will hold 5000 ounces in each pan and that will indicate the ad- dition of as slight a weight as two grains. And here is another that will balance 500 ounces in each pan and at the same time indicate the differ ence between the weights of two pieces of paper. ... .4-..
 "These are some of the tests that put American manufactured balances and scales to the front and that account for these instruments being exported An nd Tr1rn fn South America, to Mexico. to India and to Australia. All over the world, wherever science and the gold miner have penetrated, we send our scales"
 Wherein do the American made bal ances excel?" was asked.
 Chiefly in wear and In composition of very important alloy, which, like the pendulum of many clocks, is what is called 'compensating.' Bring French or a German balance to this country. and it will act like an import ed piano and many another musical in- strument The balance works excel lently while in its home country, but 1t is not adapted to the variations of climate. moisture, heat and cold that must be anticipated when manufactur- ing these instruments to be sent all over the world.
 "Who are our customers? Every chemist, every physicist, every as-S sayer and jeweler. Scientific colleges and the technical institutions use scores on scores of balances. Then there are the miners and the smelters, the silversmiths, the steel and copper nd &iv, fn dozens upon dozens of others, fnclud- ing the government departments, the geological survey, the agricultural de partment. the medical supply depart ments of the army and navy, the mint and the assay office. ..s.
 Many balances are made especially to withstand the strains peculiar to the particular work for which they are in, tended. Ordinarily a balance consists of a slim arm of brass provided at the middle with steel knife edge that rests on a higly polished plane of agate attached to the top of an upright brass pillar. stirrups of the scale pans being similarly suspended. But in a chemical balance, where the fumes of acids would attack steel, agate knife edges are substituted.
 with ordinary care and regular at- tentiOn a good balance ought to last a mans lifetime. We had a balance to repair not long ago that had been in constant use for more than forty years.
 "As much care is expended on the weights as is given to the scales. Most of the heavier weights are turned out of bars of brass and covered with lacquer that makes them practically imperviOus to attack by moisture or fumes of acids. The lighter weights consist of platinum foil, which is even more durable than brass, providing the thin, tiny pieces are handled with ordi- nary attention and care. Still, despite all precautions. the weights will fall off, and for accurate work 1t is neces- sary to test them from time to time.
 ''The diamond expert about to sail abroad for the markets of London and Paris, for example, usually buys a brand new set of weights before he quits these shores. Some of the ex- perts buy a new balance every trip to make sure they are getting an instru- ment they can rely upon. When the diamonds have been weighed and bought the scale is offered for sale in the Paris markets, and in this way the buyer gets rid of the incumbrance without loss to himself and on the next trip has the advantage of using another brand new scale."-New York Press. e... ....