658 



SPECTROGRAPHY. 



SPRINGFIELD. 



or less volatile, produce the most marked effect ; 

 but for the easily vaporized salts of the inetals, 

 such, for example, as the chloride of sodium, it 

 was found sufficient to burn an extremely small 

 quantity of it in any part of a room of ordinary 

 size, for the reaction to appear upon the spec- 

 trum as soon as any portion of the vapor could 

 reach the flame. From the quantity diffused 

 throughout the atmosphere of a room of known 

 capacity, it was calculated that the quantity of 

 vapor of chloride of sodium brought into the 

 flame in one second of time, in which the reac- 

 tion became apparent, could not have exceed- 

 ed the three-millionth part of a milligramme in 

 weight. The effect of the sodium is to produce 

 a bright and distinct yellow line across the 

 spectrum. Lithium is little less sensitive in its 

 reaction than sodium, and, what is remarkable, 

 it was found in a great variety of substances 

 examined, as in the water of springs and of the 

 . sea, in the ashes of marine plants, of tobacco, 

 of the vine, &c., and even in milk, and in hu- 

 man blood. In the mother liquors of certain 

 saline springs and of the tartaric acid manufac- 

 tories, lithia was found so concentrated as to 

 be profitably extracted. The distinctive mark 

 of lithium consists of a sharply defined, but 

 faint yellow line, and also a bright red line, 

 both near the extremity of the spectrum. Many 

 of the elements present two or more lines. 

 Potassium gives two, one in the extreme red, 

 and the other in the violet ray. Barium is 

 distinguished by two very distinct green lines ; 

 calcium by a very broad green line, and a 

 bright orange near the red end of the spec- 

 trum ; strontium by eight lines, six red, one 

 orange, and one blue. Even when the salts of 

 these metals are mixed together, the lines char- 

 acteristic of each are quite distinct, appearing 

 in succession one after another. 



Discovery of new elements by the photo-chemi- 

 cal process. Not only have these known ele- 

 ments been detected in substances in which 

 they were never before recognized, but some 

 new elements have, by means of this process, 

 been brought to light. Finding in a mineral 

 water blue lines different from those produced 

 by any known element, Bunsen and Kirchhoff 

 were at the trouble of concentrating by evapo- 

 ration full 20 tons of this water, and on analyz- 

 ing the residue obtained 240 grains of the plat- 

 inum salt of a new metal, which .they named 

 caesium from the Latin ccesius, signifying grayish 

 blue, from the color of the lines. They detect- 

 ed it in other mineral waters, and also another 

 element, which they termed rubidium, from 

 the Latin rubidus, dark red. The chemical re- 

 actions of these metals so closely resemble those 

 of potassium that they are not distinguished 

 from this by the ordinary methods of analysis. 

 The two new metals accompany each other 

 in the saline waters of Durkheimer in Ger- 

 many. Rubidium is most abundant in the 

 mineral known as lepidolite. Its atomic weight 

 by the hydrogen scale is 85'36 ; that of cesium 

 is 123'4. The latter is the most electro-positive 



element known. In subjecting native sulphur 

 to this test, Mr. William Crooks, an English 

 chemist, discovered in it the new element he 

 called thalium Gr. 0aXXor, green, from the in- 

 tense green line that it produces in the spec- 

 trum. 



Application of photo -chemical analysis to th 

 determination of the elements existing in the so- 

 lar atmosphere. In subjecting the light of the 

 sun to this method of examination, M. Kirch- 

 hoff was led to the conclusion that beneath the 

 ignited gaseous atmosphere of the sun the cen- 

 tral mass, more intensely luminous, interferes 

 with the representation of the spectrum of the 

 enveloping atmosphere, and causes the lines to 

 appear as dark which such an atmosphere 

 would otherwise present as bright. "With an 

 apparatus, however, of superior construction, 

 Kirchhoff became satisfied that the dark lines 

 in the solar spectrum contained between the 

 orange and blue, and amounting to about 70 

 particularly well-marked lines, correspond to 

 the light lines peculiar to iron, which are al- 

 ways numerous and distinct. He also recog- 

 nized the lines indicative of magnesium, chro- 

 mium, and nickel, but no distinct dark lines 

 corresponding to the very brilliant ones pro- 

 duced by cobalt, silver, lead, copper, zinc, anti- 

 mony, and aluminium. He applied the same ap- 

 paratus to experiments upon light produced by 

 the sparks from a large RuhmkorfFs induction 

 coil, and found that the spectrum thus pro- 

 duced exhibited with the greatest distinctness 

 the lines peculiar to the metals of which the 

 electrodes consisted. This method proved to 

 be especially adapted for the determination of 

 such elements as are not readily volatilized in 

 an ordinary flame. It was, however, liable to 

 a confusion from the exhibition, also, of lines 

 due to any metallic substances happening to be 

 in the air through which the spark passes. An- 

 other difficulty was also experienced in a very 

 great number of bright lines produced by every 

 electric spark, and to avoid the confusion thus 

 caused, the expedient was adopted of producing 

 two spectra from two similar pairs of elec- 

 trodes, the light of one spark being made to 

 pass through the upper, and that of the other 

 through the lower half of the slit. The effect 

 of any change introduced in one of the pairs of 

 electrodes is then immediately perceived by 

 the difference in the lines upon the two spec- 

 tra. Thus it became possible to detect the 

 presence of the rare metals, yttrium, erbium, 

 terbium, &c. ; and there is little reason to 

 doubt but the principle may be extended to 

 the detection of most of the other elements. 



SPRINGFIELD, a city and capital of Green 

 Co., Missouri, situated on the line of the S. W. 

 branch of the Pacific Railroad, 250 miles south- 

 west of St. Louis, and 130 south -south west from 

 Jefferson City. Population about 1,500. Be- 

 fore the commencement of the war it was one 

 of the finest towns in southwestern Missouri. 

 Its situation was high and healthy, and its 

 trade flourishing and rapidly increasing. It 



