240 THE POPULAR SCIENCE MONTHLY. 



few inches by rubbing it with the shell of a snail ; or the economy of 

 production, as when steel pens, sold when first introduced at one shilling 

 apiece, are now sold at a penny per dozen ; or when steel rails, lately 

 costing forty-five pounds per ton, can now be sold at five pounds. 



3. Methods of utilizing waste products, or of endowing them with 

 properties which render them of increased value to industry, as when 

 waste scrap-iron and the galls on the oak are converted into ink ; or 

 the badly-smelling waste of gas-works is transformed into fragrant 

 essences, brilliant dyes, and fertilizing manure ; or when the effete 

 matter of animals or old bones is changed into lucifer-matches. 



AH three results are often combined when a single end is obtained ; 

 at all events, economy of time and production invariably follows w^hen 

 natural forces substitute brute animal force. In industrial progress 

 the sweat of the brow is lessened by the conceptions of the brain. 

 How exultant is the old Greek poet, Antipater,* when women are re- 

 lieved of the drudgery of turning the grindstones for the daily supply 

 of corn ! " Woman ! you who have hitherto had to grind corn, let 

 your arms rest for the future. It is no longer for you that the birds 

 announce by their songs the dawn of the morning. Ceres has ordered 

 the water-nymphs to move the heavy millstones and perform your 

 labor." Penelo2:»e had twelve slaves to grind corn for her small house- 

 hold. During the most prosperous time of Athens it was estimated that 

 there were twenty slaves to each free citizen. Slaves are mere machines, 

 and machines neither invent nor discover. The bondmen of the Jews, 

 the helots of Sparta, the captive slaves of Rome, the serfs of Europe, 

 and uneducated laborers of the present day who are the slaves of igno- 

 rance, have added nothing to human progress. But, as natural forces 

 substitute and become cheaper than slave-labor, liberty follows ad- 

 vancing civilization. Machines require educated superintendence. One 

 shoe-factory in Boston by its machines does the work of thirty thou- 

 sand shoemakers in Paris, who have still to go through the weary 

 drudgery of mechanical labor. The steam-power of the world during 

 the last twenty years has risen from eleven and a half million to 

 twenty-nine million horse-power, or one hundred and fifty-two per 

 cent. 



Let me take a single example of how even a petty manufacture 

 improved by the teachings of science affects the comforts and enlarges 

 the resources of mankind. "When I was a boy the only way of ob- 

 taining a light was by the tinder-box with its quadmiple materials, 

 flint and steel, burned rags or tinder, and a sulphur-match. If every- 

 thing went well, if the box could be found and the air was dry, a light 

 could be obtained in two minutes ; but very often the time occupied 

 was much longer, and the process became a great trial to the serenity 

 of temper. The consequence of this was, that a fire or a burning lamp 

 was kept alight through the day. Old Gerard, in his " Herbal," tells 



* " Analecta Veterum Gracoruni," Epig. 39, vol. ii, p. 119. 



