In Herbert Spencer's essays on education—a most profound work noticed by us a few weeks since—we find the following exquisite paragraph on the utility of practical scicnce:—.“A grounding in science is of great importance, both because it prepares for all this and because rational knowledge has an immense superiority over empirical knowledge. Moreover, not only is it that scientific culture is requisile for each, that he may understand the how and the why of the things and pro-cesses with which he is concerned as maker or distributor ; but it is often of much moment that he should understand the how and the why ot yarions other things and processes. In this “ge of Joint stock undertakings, nendy every man above the laborer is interested us capitnlist in some other occupation than his own ; and, ns thus interested, his profit or loss often depends on his knowledge of the science bcnring on this other occupation. Here is a mine, in the sinking of which many shareholders ruined themselves from not knowing that n certain fossil belonged to the old red sandstone, below which no coni is found. Not mauy years ago, $20,000 was lost in the prosecution of a scheme for collecting the alcohol that distills from bread in baking: all of which would have been saved to the subscribers had they known that less than a hundredth part by weight of the flour is lost in fermentation. Numerous attempts have been made to construct electro-magnetic engines, in the hope of superseding steam; but had those who supplied the money understood the general law of the correlation aad equivalence of forces, they might have haJ better balances at their bankers. Daily are men induced to aid in carrying out inventions which a mere tyro in science could show to be futile. Scurcely a locality but has its history of fortunes thrown away over some impossible project." . 1 THE French photographers have succeeded in effecting an important amelioration in the art of obtaining fac-similes of olu manuscripts; recent improvements in the photographic art enabling them to produce perfectly distinct ana legible copies of the palest aud most illegible manuscripts. On old parchments, the ink, under the Influence of time, assumes a yellowish tint, which often becomes undistingltishable from that of the pnrchment, so that it cannot be read without the grpatest difficulty. Now, during the photographic process the brilliant and polished parts of the parchment reflect light much better than those Where the ink has been deposited. However colorless It may appear, the ink hns not lost its anti-photogenic qualities, opposed to the photor:enic ones of the parchmcnt; and thanks to this opposition, black churacters may be obtained on the sensitive surface, in I'eturn 1'01' much paler ones on the original. Photogmphers al'e also able to obtain, at pleasure, enlarged or diminished copies of manuscripts, pictures, statues, and ether works or art. Many roc"nt photographs, examined with the aid of a microscope, reveal particles invisible to the naked eye ; several of the lunar impressions taken during the late eelipse, and some of the solar ones, are cited as belonging to this category. Hi A RED DYE IN CHINESE SUGARCANE.—The stalks or the Chinese sorgho contain a coloring matter possessing great tinctorial power. It is prepared by fermenting the stalks of the plant from which the juice has been expressed. At the expiration of fifteen days the coloring matter is developed, and it gives a beautiful brown or red color to the stalks. They are dried to stop the fermentation, and then ground to a fine powder, which is treated with water. This l'emoves a small portion of the color. It is then treated with a weak solution of caustic soda or potassa. The base is neutmlized by sulphuric acid, and the carmine is soon deposited under the form or light flakes. The red of the sorgho is soluble in alcohol, the alkalies and feehie acids. It answers very well for dyeing silk and wool, and it appears to resist the action of light. --,-- A STEEL target, at Woohvich, weighing 30 tuns, placed on sleepers of wood, was driven back several feet on the ground by every 68-pound shot fired at a distance of 600 yards. This is a remarkable proof of the percussive power of sbot.
This article was originally published with the title "What Knowledge is Most Worth" in Scientific American 3, 26new, 404 (December 1860)