446 A SHORT HISTORY OF SCIENCE 



began to assume anything like the vast extent and importance it has 

 since reached. 



Refrigeration in various forms has been used for food preserving 

 probably from the earliest times, but the present enormous industry 

 of cold storage has all grown up since the middle of the nineteenth 

 century with the invention and development of refrigerators (domestic 

 and commercial) and especially of machines for producing and dis- 

 tributing compressed air or other vapors or brine ammonia and other 

 liquids at very low temperatures. These have been perfected rather 

 rapidly since 1860, but did not become common before 1880. The 

 first cargo of fresh meat successfully exported from America to Europe 

 was shipped in March, 1879, and from New Zealand to Europe in 

 February, 1880, arriving after a passage of 98 days in excellent 

 condition. 



THE INTERNAL-COMBUSTION ENGINE. For a century or there- 

 abouts the steam-engine stood without a rival as a thermodynamic 

 machine and prime mover. Innumerable attempts had been made 

 meantime to construct other kinds of engines to convert heat more 

 directly into power for mechanical work; but it was not until 1876 

 that the internal-combustion engine as improved by Otto became a 

 practical success. 



In the steam-engine, the furnace in which the heat is generated is 

 external to the cylinder in which that heat does its work, the steam 

 being merely an intermediary. It is therefore an external-combus- 

 tion engine. Obviously, if the fuel burned is made to liberate its 

 heat in the cylinder instead of the furnace, the steam can be dis- 

 pensed with. This is what actually happens in the internal-com- 

 bustion engine. The present enormous extent of the use of such 

 engines for motors of all kinds, testifies to the importance of this 

 invention. 



ANILINE, was first obtained from indigo in 1826 by Unverdorben 

 and named by him crystalline. In 1834 Runge prepared a similar 

 substance from coal tar, and in 1841 Fritsche obtained from indigo 

 an oil which he called aniline, a word derived from the Sanskrit 

 Nila, the indigo plant. The commercial importance of aniline in the 

 dye-stuffs industry dates from the discovery of mauve by Perkin in 

 1858. This was the first of the notable series of aniline dyes now so 

 well known, and the forerunner of the immense color industry of to-day. 



THE MANUFACTURE OF STEEL; BESSEMER. The making of steel 



