Dec. 1 8, 1873J 



NATURE 



133 



times the centre, for co-ordinated movements usually supposed 

 to be the cerebellum, or, as it is often expressed, "one man gets 

 drunk in his head, another in his legs." When the head is af- 

 fected judgment becomes impaired, though memory and imagin- 

 ation may still be more active than usual. These faculties next 

 fail, and the emotions become hilarious, pugnacious, or lachrymose. 

 The spinal cord is generally unaffected even when the cerebellum 

 is paralysed, and a man who is utterly unable to walk can still 

 ride, the mere pressure of the saddle upon his thighs being suffi- 

 cient to cause reflex contraction of his adductor muscles and fix 

 him firmly on his seat, although the upper part of his body may 

 be swaying about like a sack of wheat. The cord itself next 

 becomes paralysed, and lastly the medulla oblongata, which re- 

 gulates the respiratory movements. 



After relating an anecdote illustrative of the effects of alcohol 

 in hastening death during exposure to cold. Dr. Brunton re- 

 marked that, notwithstanding all these apparently injurious 

 actions, alcohol was of great service when properly used. 

 Many men came home from their offices completely exhausted, 

 and the stomach, sharing the general exhaustion, is unable to 

 digest the food which lies heavily in it, and incommoding instead 

 of strengthening the individual. 



A glass of sherry taken with the food will stimulate the 

 stomach to increased action, and by the time the effect of the 

 stimulus has passed away the food has digested and absorbed, 

 and sustains the effect which the alcohol temporarily produced. 

 When taken in considerable quantities for a long time, alcohol 

 is apt to produce deposit of fat and fatty degeneration of organs, 

 rendering a person not only less capable of work, but liable to 

 uccumb to disease. 



SOCIETIES AND ACADEMIES 

 London 



Royal Society, Dec. 11. — "Researches in Spectrum- 

 Analysis in connection with the .Spectrum of the Sun." — Part 

 III., by J. Norman Lockyer, F.R.S. 



The paper commences with an introduction, in which the 

 general line of work since the last paper is indicated. Roughly 

 speaking, this has been to ascertain the capabilities of the new 

 method in a quantitative direction. It is stated that while quali- 

 tative spectrum-analysis depends upon the positions of the lines, 

 quantitative spectrum-analysis on the other hand depends not on 

 position but on the lengtli, biightncss and thickness of the lines. 



The necessity of maps carefully executed and showing the 

 individuality of each line is shown ; and it is stated that the 

 execution of these maps required the use of the electric arc to 

 render the vapours of the metals incandescent. A battery of 30 

 Crove's cells of one pint capacity was accordingly employed in 

 the researches about to be described. 



The difficulties of eye-observations of the characters of the 

 lines compelled the application of photography, another reason 

 for tlie use of which existed in the facility it afforded for con- 

 fronting spectra with each other, and so eliminating coincident 

 lines, since the lines, if due to impurities, would be longest and 

 thickest in the spectrum to which they really belonged. 



The portion of the spectrum at present worked upon is that 

 from II to F. 



Another branch of the research has been the construction of a 

 Table of all the named Fraunhofcr lines, showing the lengths 

 and thicknesses of the metallic lines to the absorption of which 

 they were due ; this Table enabled the author to allocate up- 

 wards of 50 lines in the solar spectrum, presumably overlooked 

 by Angstrom and Thalen. The table was intended as a preli- 

 minary to a new photographic map of the spectrum from 11 to 

 F, on a larger scale than Angstrom's, which was intended to 

 clear away all the difficulties toucliing coincidences, and to have 

 below it complete maps of all the solar elements with their long 

 and short lines. This map is incomplete at present, but is 

 making rapid progress 



A preliminary search for elements supposed not to be in the 

 sun has also been commenced. 



Of the above-named researches the subsequent parts of the 

 paper refer to ; — 



I. The experiments made on a possible quantitative spectrum- 

 analysis. 



II. The method of photographing spectra adopted. 



III. The coincidences of spectrum lines. 



IV. The preliminary inquiry into the existence in the sun of 

 elements not previously traced. 



I. The Experiments made on a possible quantitative Spectrum- 

 Analysis 



After the two former papers were sent in to the Royal Society, 

 an investigation of the general changes undergone by spectra 

 given by alloys was commenced. 



A micrometer eye-piece was mounted on the observing- tele- 

 scope of the spectroscope. With this the following phemonena 

 were observed : — 



I. The lines which remained varied their length as the per- 

 centage of the elements to which they were due varied. 



II. Some of the lines appreciably varied their thickness or 

 brightness, or both in the same way. 



III. In cases where the brightness of a line was estimited 

 through a considerable range of percentage composition by 

 comparison with an air-line, the air-line was observed to grow 

 faint and then disappear as the lightness of the metallic lines 

 increased. 



IV. Incases where the brightness or thickness of the line of 

 one element was estimated by comparison with the line adjacent 

 of the other constituent of the alloy, the point of equal bright- 

 ness was observed to ascend or descend ; this method was used 

 to avoid the uncertainty of micrometric measurements of the 

 tips of the lines in consequence of their variation in length due 

 to the unequal action of the spark. 



V. In some cases where the percentage of a constituent was 

 so small that none of its lines were visible, there yet seemed to 

 be an effect produced on the vapour of the opposite pole. 



As these conclusions were derived from coarse alloys, and it 

 was desirable to observe the effect of very fine gradation, Mr. 

 C. Freemantle, the Deputy Master of the Mint, was begged to 

 allow observations to be made on the gold-copper and silver- 

 copper coinage alloys, and he immediately responded most 

 cordially to the request. 



Examples of the behaviour of some coarse alloys of silver 

 and lead are given ; they were irregular in their action, but it 

 was observed that silver lines remained in the alloy as long as 

 from '05 to '02 per cent, of silver was present. The alloys, 

 however, were very unequal. Experiments on cadmium and 

 tin alloys are described, the cadmium forming 10, 5, I'o, o'i5 

 per cent. In the l.ast but one cadmium line was permanent ; 

 in the first at least five were seen. In an alloy of 0^099 per 

 cent, of cadmium with a mixture of lead, tin, and zinc consti- 

 tuting the rest of the .alloy, the behaviour of the cadmium lines 

 was sensibly the same as in a mixture of O'l per cent, of cad- 

 mium and 99 '9 of tin. 



In the Mint-specimens the same phenomena were observed 

 en petit, as the coarser alloys showed en granJ. In a gold-copper 

 alloy T; 5'^1-n increase in the gold made the lines shorter, and a 

 similar increase in the copper made them longer. 



In the silver-copper alloy an increase of j^Vs "i 'he silver 

 lengthened the lines, a similar increase in the copper shortened 

 them. 



These phenomena can be explamed by assuming such alloys 

 to be different physical things, and that the spark acts upon the 

 alloy as a whole as well as upon each vapour separately. 



Thus in these Mint alloys, copper is common to both, and 

 their melting-points are :— 

 Gold . . . i200°(Pouillet). 



Copper . . 1200° to 1000°, the precise point not determined. 

 Silver . . 1000" (PouiUet). 



The intermediate position of copper explains the different 

 action on its lines of gold and silver. 



II. The Method 0/ photographing Spectra adopted 



A camera cairying a 5 X 5-inch plate and a 3-inch lens of 23 in. 

 focus, replaced the observing-tclescope of the spectroscope. 

 The lens focused from 3900 to 4500 very fairly upon the plate. 

 The beam passing through collimator and prisms was, as in 

 Mr, Rutherford's researches, very small. As tlie electric arc 

 in its usual vertical position gave all the lines from pole to pole, 

 the lamp was placed on its side, and the arc used in a horizontal 

 position, the slit being vertical. The dense core of the arc then 

 gave all the short lines in the centre of the field, the longer ones 

 extending beyond them on either side. In order to obtain a 

 scale, it was resolved to photograph the solar spectrum imme- 

 diately adjacent to the metallic spectrum under examination. 



To effect this a portion of the slit was covered up while the 

 solar spectrum passed through the free part, and then the part 

 used for the solar spectrum was covered, while the formerly 

 covered part was opened for the metallic spectrum. This was 



