172 



Lord Kelvin on Ether and 



Motions of Stars in the Line of Sight determined at Potsdam 

 Observatory, 1889-1891. (Communicated by Professor 

 Becker, University Observatory, Glasgow.) 



Star. 



a Andromeda? ... 



8 Cassiopeia} 



a Cassiopeia? 



y Cassiopeia? ...... 



8 Andromeda? ... 

 a Ursa? Minoris . 

 y Andromeda? ... 



a Arietis 



8 Persei 



a Persei 



a Tauri 



a Aurigas 



(3 Orionis 



y Orionis 



(3 Tauri 



d Orionis 



e Orionis 



£ Orionis 



a Orionis 



8 Auriga? 



y Gerninorum ... 

 a Canis Majoris . 

 a Gerninorum ... 

 a Canis Minoris . 

 (3 Gerninorum ... 

 a Leonis 



2-0 

 21 

 var. 

 20 

 23 

 2-0 

 2-4 

 20 

 var. 

 2-0 



ro 



10 

 10 

 20 

 2'0 

 2-5 

 20 

 20 

 var. 

 2-0 

 23 

 1-0 

 2-3 

 10 

 1-3 

 1-3 



Velocity 



relative to 



the Sun. 



km. 

 4- 4-5 

 + 5-2 

 -15-2 



- 3-5 

 + 11-2 

 -250 

 -129 

 -14/7 



- 1-5 

 -10-3 

 +48-5 

 +24-5 

 + 16-4 

 + 9-2 

 + 8-0 

 + 0-9 

 +26-5 

 + 14-8 

 +17-2 

 -28-1 

 -16-6 

 -156 

 -29-7 



- 9-2 

 + H 



- 91 



Star. 



y Leonis 



8 Ursa? Ma j oris 

 a Ursa? Majoris 



d Leonis 



8 Leonis 



y Ursa? Majoris. 

 e Ursa? Majoris . 



a Virginis 



£ Ursa? Majoris . 

 r) Ursa? Majoris . 



a Bootis 



e Bootis 



(3 Ursa? Minoris 



8 Libra? 



a Corona? 



a Serpen tis .... 



8 Herculis 



a Ophiuchi .... 



a Lyra? 



a Aquila? 



7 Cygni 



« Cygni 



e Pegasi 



8 Pegasi 



a Pegasi... 



20 

 23 

 2-0 

 2-3 

 2-0 

 2-3 

 20 

 1-0 

 2-1 

 20 

 10 

 20 

 2-0 

 2-0 

 20 

 2-3 

 2-3 

 2-0 

 1-0 

 1-3 

 2-4 

 1-6 

 23 

 var. 

 20 



Velocity 

 relative to 

 the Sun. 



km. 

 -38-5 

 -293 

 -11-9 

 -14-4 

 -122 

 -26-6 

 -30-3 

 -14-8 

 -31-2 

 -262 



- 7-7 

 -163 

 + 14-2 



- 9-6 

 +32-0 

 +22-3 

 -35-3 

 + 19-2 

 -15-3 

 -36-9 



- 64 



8-0 

 8-0 

 6-7 

 1-3 



The velocity of the sun relatively to stars in general accord- 

 ing to Kempf and Eisteen is probably about 19 kilometres 

 per second. In respect to greatest proper motions and velo- 

 cities Sir Norman Lockyer gives me the following informa- 

 tion : — " The star with the greatest known proper motion 

 " (across the line of sight) is 243 Cordoba = 8"'7 per annum. 

 " Velocity in kilometres not known. 



u 1830 Groombridge has a proper motion of 7"*0 per 

 " annum and a parallax of 0"*089, from which it results that 

 " the velocity across the line of sight is 370 kms. per second. 

 " Various estimates of the parallax, however, have been 

 u made and this velocity is somewhat uncertain. The star 

 " with the greatest known velocity in the line of sight is £ 

 u Herculis, which travels at 70 kms. per second. 



" The dark line component of Nova Persei was approaching 

 u the earth with a velocity of over 1100 kms. per second." 



