June 1965

Interior of the Earth “Our experiments with the 90:10 iron-nickel alloy and extrapolations from these results indicate that under the assumed high pressures and temperatures of the earth's core the density of the alloy is about 10 percent less than that of pure iron. Our density values for this alloy agree with the density of the core, as estimated by K. E. Bullen of the University of Sydney and Francis Birch of Harvard University on the basis of seismic data, the moment of inertia and the earth's mass. We conclude, therefore, that the earth's core probably consists of iron-nickel alloys and is similar in composition to the iron-nickel meteorites.”

June 1915

The Greatest Invention? “The most significant event in the annals of human achievement was the invention of the steam engine. Its introduction divided recorded time into two distinctly defined eras, and it may well be said that the entire history of man's material endeavors counts forward or backward from that comparatively recent event. The jump from manual to power operations, which typifies the two eras, was nothing short of cataclysmic, and profoundly affected and stirred mankind in all its relations to an extent inconceivably greater than any political change or decision in battle that is ordinarily cited by the historian to mark the beginning of a new epoch.”

Our 70th Anniversary “When we think that at the time the SCIENTIFIC AMERICAN was started it took three weeks to send a message from New York to Liverpool and three months to Calcutta; when we think that only yesterday we marveled at the application of ether and chloroform to surgery, at the feat of telegraphing across the ocean without wires, at the bigness of the Panama Canal, at the opportunity of viewing the skeleton beneath the living flesh with the X-rays, and the spectacle of a man flying in the air swifter than any bird; when we think that it has been our privilege not merely to see these and many other miracles but to translate them into print, who can blame us if we contemplate our future task with a feeling almost akin to awe?”

June 1865

Interior of the Earth “Messrs Editors—For my own part I have quite a ‘golden’ idea—that the interior of the earth is abundantly supplied with, if not mainly composed of, gold, platinum and other precious metals. If we suppose but for an instant that the earth was once in a gaseous or fluid state, is it not quite evident that those substances most difficult of fusion, and possessing the greatest specific gravity, would be first to find their way to the center? Now gold, platinum and a few other of the precious metals possess these properties in a high degree above all other known substances, and though we know them to be scarce on the surface of the earth, we have no assurance but that they are abundant in nature.—John Calvin Moss”

The writer invented the first successful photoengraving process for printing.

Plowing with Steam Engines “Difficulties have been met with in applying steam power to cultivation. To attach the moving power direct to the implement, as is done in the case of the horse, was found not suitable with a steam engine, from the loss of power in moving such a heavy weight over inequalities of the ground, and from the compression caused by its travelling over the soil to be cultivated. Hence the use of a rope driven by the engine became requisite for working the implement.”

Varnish Ingredient “The purest and best gum copal in the world is found on the mainland of Africa, near Zanzibar. It is, without doubt, a fossil gum. It is dug from the earth by Africans, and by them carried to the Banian [Indian] trader, in small quantities, for sale. When it reaches Zanzibar, it is in a very dirty state, and requires much sifting and garbling before it is merchantable; it is then cleansed with a solution of soda-ash and lime, put up carefully in boxes, when it is ready for the home market. That it is a gum may be proved from the fact of its rough or ‘goose-skin’ surface, which no doubt is an impression of the sand or earth when it ran down from the tree in a soft state. Pieces, too, are found with sticks, leaves, and insects preserved in them in the most perfect state.”