SCIENCE, INVENTION, DISCOVERY, 



319 



colleges and universities in the United States 

 and Europe within a recent period. 



Etching', Art of. About the middle of 

 the fifteenth century Tomaso Finiguerra, a 

 Florentine, introduced the art of etching. In 

 Germany, Italy, and France its value met with 

 prompt recognition, but it was not carried 

 to a state of perfection till later times. It was 

 at first regarded as an industrial art, but it 

 soon grew to have a higher value, reproducing 

 in graceful freedom and precision of touch the 

 very feeling of the artist. The first step in 

 etching is to cover the plate with a composi- 

 tion of wax, asphaltum, gum-mastic, resin, 

 etc., dissolved by heat. An outline of the 

 design, made on paper in pencil or red chalk, 

 is then "transferred" to the surface of this 

 composition by being passed through a press. 

 The subject is then drawn on the ground with 

 the etching point, which cuts through it and 

 exposes the copper. Etching-points or nee- 

 dles resemble large sewing needles shortened 

 and fixed into handles four or five inches long. 

 Some are made oval, to produce broader lines. 

 A rim of wax being put around the plate, acid 

 is poured on, and corrodes the copper not pro- 

 tected by the ground. If the acid is found not 

 to have acted sufficiently, it may be applied 

 again to the whole design, or only to portions 

 of it, by stopping up with a mixture of lamp- 

 black and Venice turpentine, applied with a 

 camel's-hair pencil, what has been sufficiently 

 bitten-in. When a series of parallel lines are 

 wanted, as in backgrounds, etc., an ingenious 

 machine called a ruler is employed, the accu- 

 racy of whose operation is exceedingly perfect. 

 This is made to act on the etching-ground by 

 a point or diamond connected with the appa- 

 ratus, and the tracings are bit in with aqua 

 fortis in the ordinary way. The art of etching 

 was popularized by Sandro Botticelli, who em- 

 bellished an edition of ' ' Dante ' ' with etching 

 illustrations about the end of the fifteenth cen- 

 tury. The great German etchers of that time 

 were Shoengauer, Bechellin, and Wohlgemuth, 

 and the Italian representatives were Bacio 

 Baldini, Pollajuoli, and Montegna. In the 

 succeeding century Goltzius and others repro- 

 duced the works of the old masters, through 

 etching, with wonderful mobility. Toward the 

 latter end of the seventeenth century the art 

 was carried to a high degree of perfection by 

 Le Bas and by the Spanish school. Then, for 

 a time, the art declined, its place being taken 

 by steel engraving, which in turn gave way to 

 the chromo, and that to the lithograph. The 

 revival of the art in England is largely due to 

 Philip Gilbert Hamerton. At that time Sey- 

 mour Haden was the leading etcher in Eng- 

 land, as was Count de Gravesande in France. 



"Whistler, the eccentric American, is now one 

 of the leading lights in the art in England, 

 and Hamilton Hamilton is probably the most 

 popular etcher in America. Among'the great- 

 est of modern etchers are Salonne, Couteau, 

 Waltner, Rajon, De Baines, and Koepping. 



Ether was known to the earliest chemists. 

 Nitric ether was first discovered by Kunkel, in 

 1681 ; and muriatic ether, from the chloride 

 of tin, by Courtanvaux in 1759. Acetic ether 

 was discovered by Count Lauraguais, same 

 year; and hydriodic ether wfcs first prepared 

 by Gay-Lussac. The phosphoric was obtained 

 by M. Boullay. Ether is said to have been 

 first applied to the purpose of causing insensi- 

 bility to pain by Dr. Horace Wells of Connec- 

 ticut, in 1846. The discovery that by inhaling 

 ether the patient is rendered unconscious of 

 pain, is due to Dr. Charles T. Jackson, of 

 Boston ; but to Dr. Morton of the same place, 

 probably belongs the credit of first demonstrat- 

 ing, by actual experiment, the use of ether in 

 dentistry and surgery. The practice was 

 first copied in Europe by Dr. Robertson, 

 of Edinburgh, and Dr. Booth, of London, in 

 1846. 



Ethnology is the science which treats of 

 the division of man into races, with their ori- 

 gin, relations, and characteristics. Natural- 

 ists divide mankind, according to certain 

 physical characteristics, into varieties, or races. 

 Authorities differ greatly in this classification. 

 Cuvier made three races ; Pritchard, seven ; 

 Agassiz, eight, and Pickering, eleven ; but 

 the classification most commonly accepted is 

 that into five races, as made by Blumenbach, 

 as follows : The Caucasian, European; or white 

 race; the Mongolian, Asiatic, or yellow race; 

 the Ethiopian, African, or black race ; the 

 American Indian, or red race ; the Malay, or 

 brown race. The first three are much more 

 clearly marked, and are considered by Guyot 

 as primary races ; the others, being modifica- 

 tions of these three, he designates as secondary 

 races. Because of the blending of types, it is 

 difficult to make a classification , hence the dif- 

 ference among authorities. The points on 

 which the classification is based are mainly the 

 size and proportions of the body, the shape of 

 head and the features, the hair and beard, and 

 the color of the skin. 



The Caucausian race is characterized by 

 tall stature, oval head and face, high forehead, 

 regular features, abundance and softness of 

 hair and beard, and usually fair skin, but in 

 some it is tawny or swarthy, as in the Hindoos, 

 Arabs, and others. This race stands at the 

 head in intelligence and civilization. It is rep- 

 resented by the principal inhabitants of Europe 

 and their descendants in America, and by the 



