This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1877 edition. Excerpt: ...spot E 2 a 68 ssacrnou or run sux's'sPo'rs. ' _ ' within the slit S S' in the right hand figure. The spectrum of this portion will consist of a number of images of S S' ranged side by side, so as to form such a strip as RV in fig. 43: at the top and bottom of this spectrum there will be two narrow ...
Read More
This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1877 edition. Excerpt: ...spot E 2 a 68 ssacrnou or run sux's'sPo'rs. ' _ ' within the slit S S' in the right hand figure. The spectrum of this portion will consist of a number of images of S S' ranged side by side, so as to form such a strip as RV in fig. 43: at the top and bottom of this spectrum there will be two narrow solar spectra corresponding to the parts S P and S' P'; next to these will be two narrow spectra of the penumbral parts of the spot, P U and P' U'; and in the middle there will be a narrow spectrum corresponding to the umbral part UU'; all these spectra forming one compound spectrum. The first to apply this method to the solar spots was Mr. Lockyer, who, in 1866, discovered that the spectrum of the dark parts of spots is the same in general as the spectrum of the brighter portions of the sun's surface, but fainter, showing that the darkness is in the main due to general absorption (or feebler emission on account of reduced temperature). And as the darker parts of the spots give the fainter portions of the spectra, it is clear that the absorption (or the enfeeblement of emission) is proportioned to the apparent darkness of the spots. Thus the cause of the darkness of the spots is shown not to be, as was supposed by some continental astronomers, the vaporisation of the matter of the solar photosphere, but either the interposition of relatively cool matter exercising a general absorption, or else a cooling of portions of the photosphere. But besides the enfeeblement of the solar spectrum, where there is a spot, there are signs also of increased absorption by some of the vapours which cause the dark lines. Thus the D lines are notably widened, in the manner illustrated (in the case of a hydrogen line)...
Read Less
Add this copy of The Spectroscope and It's Work to cart. $25.09, new condition, Sold by Books2anywhere rated 5.0 out of 5 stars, ships from Fairford, GLOUCESTERSHIRE, UNITED KINGDOM, published 2017 by Hansebooks.
Choose your shipping method in Checkout. Costs may vary based on destination.
Seller's Description:
PLEASE NOTE, WE DO NOT SHIP TO DENMARK. New Book. Shipped from UK in 4 to 14 days. Established seller since 2000. Please note we cannot offer an expedited shipping service from the UK.
Add this copy of The Spectroscope and it's Work to cart. $26.31, new condition, Sold by Ingram Customer Returns Center rated 5.0 out of 5 stars, ships from NV, USA, published 2017 by Hansebooks.
Add this copy of The Spectroscope and it's Work to cart. $27.34, new condition, Sold by Booksplease rated 3.0 out of 5 stars, ships from Southport, MERSEYSIDE, UNITED KINGDOM, published 2017 by Hansebooks.
Add this copy of The Spectroscope and It's Work to cart. $27.37, new condition, Sold by Paperbackshop International rated 4.0 out of 5 stars, ships from Fairford, GLOS, UNITED KINGDOM, published 2017 by Hansebooks.
Choose your shipping method in Checkout. Costs may vary based on destination.
Seller's Description:
PLEASE NOTE, WE DO NOT SHIP TO DENMARK. New Book. Shipped from UK in 4 to 14 days. Established seller since 2000. Please note we cannot offer an expedited shipping service from the UK.
Add this copy of The Spectroscope and It's Work to cart. $49.89, good condition, Sold by Bonita rated 4.0 out of 5 stars, ships from Newport Coast, CA, UNITED STATES, published 2017 by hansebooks.
