Gambar halaman
PDF
ePub

K.

3:1639
3.0536
3.0129
3.1079

Common plate

, { No:2

}

3.2431

.2.2838

Results.
Dielectric
Glass, Slabs about 1 inch
thick,

Double extra dense flint
Chance's optical Extra dense flint.....
glass.

Light flint.....
Hard crown..

No. 1 3.2581
2 slabs.

3.2282

No. 1 2.2697
Ebonite, 4 slabs, J No. 2 2 .2482
1,1,1, 1 inch No. 3 2:3097

No. 4 2:3077
Best quality gutta percha
Chatterton's compound

black
India-rubber
Solid paraffin, sp.
gr. at 11° C.:9109. No. 1 1.9940
Melting point No. 2 1.9784
68° C. 6 slabs cut No. 3 1.9969
in planing ma-

No. 4 2 .0126
chine. Results No. 5 1.9654
corrected for ca- No. 6 2.0143
vities.
Shellac ...
Sulphur
Bisulphide of carbon

2:4625
2 •5474
2 .2200
2.4969

Mean ...1.9936*

2 .7464
2:5793
1.80967

[ocr errors]

The following table compares the refractive indices of the transparent dielectrics with the square roots of the specific inductive capacities. In cases where there is a wide difference u is taken from books on physics ; wherever there was a close agreement it was carefully determined by the author, except in the case of paraffin, where the value is that given in Maxwell's “ Electricity.”

* Messrs. Gibson and Barclay, “Phil. Trans.,"1871, using a method entirely different from mine, obtained K =1.977 for paraffin. Correcting for a slight difference of density, I find that if they had used my paraffin their result would have been 1.9833.

+ I am not quite certain of the accuracy of this result.

[merged small][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small]

VI. “Researches in Spectrum Analysis in connexion with the

Spectrum of the Sun. No. VII.” By J. N. LOCKYER,
F.R.S. Received December 11, 1878. Read December 12.

Discussion of the Working Hypothesis that the so-called Elements are

Compound Bodies.

PART I. It is known to many Fellows of the Society that I have for the last four years been engaged upon the preparation of a map of the solar spectrum on a large scale, the work including a comparison of the Fraunhofer lines with those visible in the spectrum of the vapour of each of the metallic elements in the electric arc.

To give an idea of the thoroughness of the work, at all events in intention, I may state that the complete spectrum of the sun, on the scale of the working map, will be half a furlong long ; that to map the metallic lines and purify the spectra in the manner which has already been described to the Society, more than 100,000 observations have been made and about 2,000 photographs taken.

In some of these photographs we have vapours compared with the sun ; in others vapours compared with each other; and others again have been taken to show which lines are long and which are short in the spectra.

I may state by way of reminder that the process of purification consisted in this: When, for instance, an impurity of Mn was searched for in Fe, if the longest line of Mn was absent, the short lines must also be absent on the hypothesis that the elements are elementary ; if the longest line were present, then the impurity was traced down to the shortest line present.

Table I. Final reduction-Iron.

Intensity in Sun.

Coincidences with Short Lines.

1

[blocks in formation]

3

2

[blocks in formation]

2

Co 3

Mn Ce 3 4

2

2

Os

2

1

2

1

Mo 3

Ce

3

[merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small]

Wavelength

and length of line.

33 0600

2 0622

4 0920

3 1010

1648

2 1755

3 1835

2700

1 2950

1 3023

4 3435

4 3475

2 3628

3 3975

2 4026

3 4422

4720

2 5012

2 5160

2 5210

3 5423

6215

3 6571

2 6662

2 7555

3 7578

4 7685

2 8083

2 8320

9520

3 9750 2

.............. Ru

3

[blocks in formation]

Table II. Final reduction Titanium.

Intensity Wave-length

and length

of line.

Coincidences with Short Lines.

in Sun.

Zr

[ocr errors]

Th

5

[blocks in formation]

2

Va 4

Ce

5

[blocks in formation]

4

.....

3

3

[blocks in formation]

39 0000

3 0048

3 1040

5 1360

3 1915

8 2050

3 2368

2 3718

5 4775

1 5722

1 6175

2 6335

2 8083

1 8152

2 8922

1 9798 longest

[merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small]

The Hypothesis that the Elements are Simple Bodies does not include all

the Phenomena. The final reduction of the photographs of all the metallic elements in the region 39-40—a reduction I began in the early part of the present year, and which has taken six months, summarised all the observations of metallic spectra compared with the Fraunhofer lines accumulated during the whole period of observation. Now this reduction has shown me that the hypothesis that. identical lines in different spectra are due to impurities is not sufficient. I shall show in detail in a subsequent paper the hopeless confusion in which I have been landed. I limit nyself on the present occasion to giving tables showing how the hypothesis deals with the spectra of iron and titanium.

We find short-line coincidences between many metals the impurities of which have been eliminated, or in which the freedom from mutual impurity has been demonstrated by the absence of the longest lines.

Evidences of Celestial Dissociation. It is five years since I first pointed out that there are many facts and many trains of thought suggested by solar and stellar physics which point to another hypothesis, namely, that the elements themselves, or at all events some of them, are compound bodies.

In a letter written to M. Dumas, December 3, 1873, and printed in the Comptes Rendus, I thus summarised a memoir which has since appeared in the Philosophical Transactions.

“Il semble que plus une étoile est chaude plus son spectre est simple, et que les éléments métalliques se font voir dans l'ordre de leurs poids atomiques.*

" Ainsi nous avons :

“1. Des étoiles très-brillantes où nous ne voyons que l'hydrogène, en quantité énorme, et le magnésium ; “2. Des étoiles plus froides, comme notre Soleil, où nous trouvons:

H+Mg+Na

H+Mg+Na+ Ca, Fe, ...; dans ces étoiles, pas de métalloïdes;

“3. Des étoiles plus froides encore dans lesquelles tous les éléments talliques sont ASSOCIÉS, où leurs lignes ne sont plus visibles, et où nous n'avons que les spectres des métalloïdes et des composés.

“4. Plus une étoile est âgée, plus l'hydrogène libre disparaît ; sur la terre, nous ne trouvons plus d'hydrogène en liberté.

" Il me semble que ces faits sont les preuves de plusieurs idées émises par vous.

J'ai pensé que nous pouvions imaginer une dissociation céleste, qui continue le travail de nos fourneaux, et que les métalloïdes sont des composés qui sont dissociés par la température solaire, pendant que les éléments métalliques monatomiques, dont les poids atomiques sont les moindres, son précisément ceux qui résistent, même à la température des étoiles les plus chaudes."

Before I proceed further, I should state that while observations of the sun have since shown that calcium should be introduced between hydrogen and magnesium for that luminary, Dr. Huggins' photographs have demonstrated the same fact for the stars, so that in the present state of our knowledge, independent of all hypotheses, the facts may be represented as follows, the symbols indicating the spectrum of which the lines are visible :

Hottest Stars
Sun
Cooler Stars

Lines of

H+Ca+Mg
H+ Ca + Mg+Na+ Fe

Mg+Na+ Fe + Bi+Hg

Coolest

Fluted bands of

Metalloids

* This referred to the old numbers in which Mg=12, Na=23.

« SebelumnyaLanjutkan »