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Cbciuiati, 0. irS EASY TO MAKE BIG SPARE TIME MONEY Send for our free plan on how to make $5.00 to $15.00 a week in your spare time by taking orders for Popular Science Monthly from your friends. No selling required. Turn extra hours into extra dollars. POPULAR SCIENCE MONTHLY 381 Fourth Ave. New York, N. Y. MICROSCOPE DETECTIVES (Continued from paRe .36) trousers and under the microscope compared bits taken from the pocket-linings with the fiber specimens found in the guns. We not only proved the weapons belonged to the gangsters but we knew which gun belonged to which man." In order to aid sleuths in identifying strange fibers, Frank Gompert, of the sheriff's office in Los Angeles, Calif., has collected specimens from all over the world. His unique "fiber museum" is said to contain upwards of 200,000 samples. I LEARNED that often the microscope is called upon to examine bits of fiber under strange circumstances. In an eastern city, not long ago, a demonstrator for a company making bullet-proof vests sued his wife for divorce. Unfortunately, he failed to wear one of the vests he demonstrated in court. While he was testifying on the stand, his wife leaped to her feet, whipped a revolver from her purse and fired two shots. One went wild. The other ripped through the upper part of her husband's left lung. After a week in the hospital, it was thought he was on his way to recovery when he took pneumonia and died. Had the shooting caused the pneumonia? That was the problem for the court. To find out, experts scraped the inside of the wound, made microscopic tests and found that fibers from the outer clothing of the victim had been carried into his chest, thus introducing the germs. The woman was held on a charge of murder. Again, the versatile microscope plays a part in crime-solving by examining fibers and threads when fabrics have been cut or torn. Seen under a high-powered lens, a cut that looks perfectly straight to the naked eye appears as a jagged line. When the two halves are placed together, the thousand and one projections and indentations dovetail. By this test, a murderer who wrapped his victim's body in a strip of canvas was run to earth. In another case, the revolver of a gunman was traced through a strip of tape wound around the handle. One end of the strip, under the microscope, matched the end of a roll from which it had been torn in the house of the suspect. Paper fibers also often form a prize exhibit in the microscope-rooms of the crime labo- ratories. For instance, when a paper is creased the fibers are stretched at the point of the fold, and an expert, by examining a document at this place, can instantly tell if writing has been added after the paper was folded. Usually, the ink runs slightly where the fibers are pulled apart. Sometimes, on hard-sur- faced papers, there is a microscopic gap in the ink line at the bottom of the crease where the pen has jumped over the "ditch." While visiting one eastern handwriting laboratory, I was recently shown a "per- fect forgery." A forty-year-old note, held against an estate, had been raised from S10,000 to $100,000. The shape, size, and formation of the forged figures and letters would have fooled the most expert eye. The ink that had been used was identical with the original. Yet, when I peered into the round lens of the expert's microscope, I saw an instant proof of fraud. The paper fibers had been swelling and shrinking with forty years of alternate dampness and dryness. As a result, the ink of the original writing con- tained tiny cracks, Lilliputian canyons that split open the black ridges forming the letters and figures. But in the newer, added, writing, there was not a single crack ! In a score of other ways, microscope enlargements reveal forgeries. They expose retouched spots on fake signatures. They reveal slips made in reproducing legal seals, in printing counterfeit bills and in making spurious coins. Frequently, I was told, ace sleuths, in solving a crime, never go near the spot marked "X." They labor in their labora- tories, painstakingly examining evidence sub- mitted by trained assistants. In this manner, the late Dr. Albert Schneider, head of the noted Berkeley, Calif., crime detection labo- ratory, revealed the secret of a fiendish mur- der plot. On a fall morning, shortly after nine o'clock, a number of people saw two men, a well-known chemist and a newly-hired assistant, enter the small laboratory where the scientist was conducting experiments with volatile liquids. Two hours later, neighbors rushed into the streets at the sound of an explosion. Livid sheets of chemical-fed flames streamed from the windows of the building. The fire had practically destroyed the structure before help arrived. Hacking their way into the smouldering ruins, firemen recovered a single charred body. Through vestiges of clothing found under it, and a ring on the right hand, it was identified as that of the chemist. His assistant had dis- appeared. T IFE insurance companies, a short time A-i before, had written large policies on the life of the scientist. They asked Dr. Schneider to make an investigation. From the back of the victim's head, where it had been partially protected by a soaked blanket, an assistant brought him three unburned frag- ments of hair. Another assistant obtained from the home of the chemist a hairbrush he had used. Combings from it were compared under a microscope with the fragments taken from the body. The results became instan- taneous headline news. The chemist's hair. Dr. Schneider found, was fine, round and straight. The fragments taken from the head of the dead man were greater in diameter and oval in shape, indi- cating the victim's hair was curly. To the trained eye of the detective, this evidence proved conclusively the dead man could not have been the chemist. The papers announcing this sensational discovery were hardly on the streets before a flash from Portland, Ore., sent the presses racing again. In a downtown hotel, there, a stranger had committed suicide. He had been identified as the missing chemist. His written confession revealed the whole fiendish scheme, hatched to defraud the insurance companies. IN HIS laboratory, the plotter had mur- dered his assistant, hired because he was his double in size and weight. Then he had placed his clothes and ring on the body of his victim. After pouring ether and carbon- disulphide around the body, he had escaped unnoticed, leaving a time mechanism to ignite the volatile chemicals. With a host of such dramatic exposures to its credit, the microscope has proved itself the standby of the scientific sleuth. Its world of invisible clues is solving an ever- increasing number of baffling crimes. In the hands of the painstaking, scientific crime- fighters of the laboratory, it has become a major weapon in the offensive against crooks. j1 SiTRONOMY solves a mysterious murder Entomology unravels a baffling crime Read, in the next installment of this thrilling series, how strange, unex- pected applications of science give clues to the wanted criminal. Out December First. Order your January Popular Science Monthly in advance. 142 POPULAR SCIENCE MONTHLY