Certain effects were known to usually follow the giving of certain drugs, or the application of certain measures, but why or how these effects were produced, was unknown. The great steps forward have been made upon the true scientific foundation established by the discoveries and inventions in the fields of physics, chemistry and biology. The discovery of anaesthetics and their application in surgery and the practice of medicine, no doubt constitutes the leading invention of the century in this field. Sir Humphry Davy suggested it in 1800, and Dr. W. T. Morton was the first to apply an anaesthetic to relieve pain in a surgical operation, which he did in a hospital in Boston in 1846. Both its original suggestion and application were also claimed by others. Not only relief from intense pain to the patient during the operation, but immense advantages are gained by the long and careful examination afforded of injured or diseased parts, otherwise difficult or impossible in a conscious patient. The exquisite pain and suffering endured previous to the use of anaesthetics often caused death by exhaustion. Many delicate operations can now be performed for the relief of long-continued diseases which before would have been hazardous or impossible. How many before suffered unto death longdrawn-out pain and disease rather than submit to the torture of the knife! How many lives have been saved, and how far advanced has become the knowledge of the human body and its painful diseases, by this beneficent remedy! Inventions in the field of medicine consist chiefly in those innumerable compositions and compounds which have resulted from chemical discoveries. Gelatine capsules used to conceal unpalatable remedies may be mentioned as a most acceptable modern invention in this class. Inventions and discoveries in the field of surgery relate not only to instrumentalities but processes. The antiseptic treatment of wounds, by which the long and exhausting suppuration is avoided, is among the most notable of the latter. In instruments vast improvements have been made; special forms adapted for operation in every form of injury; in syringes, especially hypodermic, those used for subcutaneous injections of liquid remedies; inhalers for applying medicated vapours and devices for applying volatile anaesthetics, and devices for atomising and spraying liquids. In the United States alone about four thousand patents have been granted for inventions in surgical instruments. Dentistry. This art has been revolutionised during the century. Even in the time of Herodotus, one special set of physicians had the treatment of teeth; and artificial teeth have been known and used for many ages, but all seems crude and barbarous until these later days. In addition to the use of anaesthetics, improvements have been made in nearly every form of dental instruments, such as forceps, dental engines, pluggers, drills, hammers, etc., and in the means and materials for making teeth. Later leading inventions have reference to utilising the roots of destroyed teeth as supports on which to form bridges to which artificial teeth are secured, and to crowns for decayed teeth that still have a solid base. There exists no longer the dread of the dentist's chair unless the patient has neglected too long the visit. Pain cannot be all avoided, but it is ameliorated; and the new results in workmanship in the saving and in the making of teeth are vast improvements over the former methods. CHAPTER VII. STEAM AND STEAM ENGINES. "Soon shall thy arm, unconquered steam! afar THUS sang the poet prophet, the good Dr. Darwin of Lichfield, in the eighteenth century. Newcomen and Watt had not then demonstrated that steam was not unconquerable, but the hitching it to the slow barge and the rapid car was yet to come. has come, and although the prophecy is yet to be rounded into fulfilment by the driving of the "flying chariot through the field of air," that too is to come. It The prophecy of the doctor poet was as suggestive of the practical means of carrying it into effect as were all the means proposed during the first seventeen centuries of the Christian Era for conquering steam and harnessing it as a useful serv ant to man. Toys, speculations, dreams, observations, startling experiments, these often constitute the framework on which is hung the title of Inventor; but the nineteenth century has demanded a better support for that proud title. He alone who first transforms his ideas into actual work and useful service in some field of man's labor, or clearly teaches others to do so, is now recognised as the true inventor. Tested by this rule there was scarcely an inventor in the field of steam in all the long stretches of time preceding the seventeenth century. And if there were, they had no recording scribes to embalm their efforts in history. We shall never know how early man learned the wonderful power of the spirit that springs from heated water. It was doubtless from some sad experience in ignorantly attempting to put fetters on it. The history of steam as a motor generally commences with reference to that toy called the aeolipile, described by Hero of Alexandria in a treatise on pneumatics about two centuries before Christ, and which was the invention of either himself of Ctesibius, his teacher. This toy consisted of a globe pivoted on two supports, one of which was a communicating pipe leading into a heated cauldron of water beneath. The globe was provided with two escape pipes on diametrically opposite sides and bent so as to discharge in opposite directions. Steam admitted into the globe from the cauldron escaped through the side pipes, and its pressure on these pipes caused the globe to rotate. Hero thus demonstrated that water can be converted into steam and steam into work. Since that ancient day Hero's apparatus has been frequently reinvented by men ignorant of the early effort, and the principle of the invention as well as substantially the same form have been put into many practical uses. Hero in his celebrated treatise described other devices, curious siphons and pumps. Many of them are supposed to have been used in the performance of some of the startling religious rites at the altars of the Greek priests. From Hero's day the record drops down to the middle ages, and still it finds progress in this art confined to a few observations and speculations. William of Malmesbury in 1150 wrote something on the subject and called attention to some crude experiments he had heard of in Germany. Passing from the slumber of the middle ages, we are assured by some Spanish historians that one Blasco de Garay, in 1543, propelled a ship having paddle wheels by steam at Barcelona. But the publication was long after the alleged event, and is regarded as apocryphal. Observations became more acute in the sixteenth and seventeenth centuries, experiments more frequent, and publications more full and numerous. Cardan Ramelli and Leonardo da Vinci, learned Italians, and the accomplished Prof. Jacob Besson of Orleans, France, all did much by their writings to make known theoretically the wonderful powers of steam, and to suggest modes of its practical operation, in the latter part of the sixteenth century. Giambattista della Porta, a gentleman of Naples, possessing high and varied accomplishments in all the sciences as they were known at that day, 1601, and who invented the magic-lantern and camera obscura, in a work called Spiritalia, described how steam pressure could be employed to raise a column of water, how a vacuum was produced by the condensation of steam in a closed vessel, and how the condensing vessel should be separated from the boiler. Revault in France showed in 1605 how a bombshell might be exploded by steam. Salomon de Caus, engineer and architect to Louis XIII, in 1615 described how water might be raised by the expansion of steam. In 1629 the Italian, Branco, published at Rome an account of the application of a steam jet upon the |