February 1962

Error Codes
“Until quite recently the engineer who wanted to improve the quality of a communication channel concentrated his attention on reducing noise, or, to be more precise, on increasing the signal-to-noise ratio. The most direct way to achieve this is to increase the power of the signal. Within the past 15 years a host of new signal-processing devices—notably the electronic computer—have stimulated a different approach for transmitting signals with a minimum of error: the use of error-detecting codes. The principle underlying such codes has a long history. What is new is (1) a body of theory that tells the engineer how close the codes come to ideal performance and (2) techniques for constructing codes.”

Hiding Nukes
“It appears increasingly doubtful that an atomic-weapons test of significant dimension can be concealed either underground or in outer space. A five-kiloton nuclear explosion in an underground salt cavern near Carlsbad, N.M., in December was clearly recorded by seismographs as far away as Tokyo, New York, Uppsala in Sweden and Sodankyla in Finland. The seismograph records included tracings of the ‘first motion,’ considered critical in distinguishing between earthquakes and underground explosions.”

February 1912

Machine Replaces Muscle
“Probably no agricultural development of the last decade is of more interest or greater significance than the rapid advance in the use of the traction engine. The coming of the gas tractor was the first step in making power farming universally possible. The old-time thresherman was little more than a stationary engineer. With the coming of the all-purpose tractor, his duties multiplied. Besides keeping his engine in trim, he had to learn to drive straight, avoid holes and obstructions, and above all to earn money for the owner of the outfit by keeping it eternally on the move. Out of the necessity has grown a new type—a farmer-engineer of high caliber, tersely termed a ‘tractioneer.’”

Vickers Machine Gun
“Recently an improved type of the familiar Vickers light automatic rifle-caliber gun has made its appearance, and commands attention owing to its greater mobility and ingenious tripod. An appreciable reduction in weight has been also effected, for whereas the older weapon ready for use weighed 69 pounds, the new gun weighs only 36 pounds. This lessening of weight has been obtained by the use of high-class steel instead of gunmetal in the construction of all the parts.”

This water-cooled machine gun was used extensively during World War I, which broke out two years later. For a look into our archives at the technology of weapons and warfare in 1912, see the slideshow at www.ScientificAmerican.com/feb2012/warfare

February 1862

Does it Work for Shrapnel Wounds?
“The Committee on Military Affairs in the house of Representatives have under consideration the expediency of intro­ducing the system of Samuel Hahnemann [homeo­pathy] into the army. It was agreed to authorize Mr. Dunn to report a bill instructing the Medical Bureau of the War Department to permit, under certain restrictions as to number and qualifi­cations, the employment of graduates of regular Homeopathic colleges as army surgeons. This measure has been fought bitterly in committee, and has for its opponents the entire present medical force of the army. We understand that Gen. McClellan, who is a firm believer in homeopathy, is anxious to have the system tested in the army. Why not try it? It has thousands of firm believers in the country, and is rapidly gaining ground.”

Salt and Slush
“The practice of salting the tracks of city railroads, where­by they have been kept in a state of cold slush during winter, has called forth the wisdom of various city magis­trates and others in exposing the evils, or supposed evils, arising therefrom. The Common Council of Phila­delphia called in scientific experts to give testimony. Professor Rand, of the Franklin Institute, did not believe there was any increase of mortality among children from catarrhal diseases since the use of salt upon the rail­roads. The difference between salt and no salt is, that with salt you may have only have one day’s slush, where the slush would last a week without it.”