W. Harkness—The Solar Parallax. 377 
1672, J. D, Cassini. (MAc, Pili tide es a a a, 9"°5 
1751. Lacaille (Ephémérides des Mouvements Célestes 
depuis 1765 jusqu’en 1774. Paris. Introd. p. 1), 10°38 
1835. Henderson (MAS, viii : 
1856. Gilliss and Gould (U. 8. Ast. Ex, to the South. 
Hemisphere, vol. iii, p. celxxxviii), -----..--.--- "495 
1863. Winnecke (ANn, Bd. lix, ot ees hia et Be 8-964 
1865. E. J. Stone (MAS, vol. xxxiii, p. 97), 8°943 
1865, A. Hall (WOb, 1863, App. p. Igi¥)y--- os 8°842 
1867. Newcomb (WOb, 1865, er AD, ee 82) es eee 8°855 
1879. Downing (ANn, Ba. novi, a. E97)52 55.2.0 a 8-960 
The following are some of the results from the diurnal 
method: 
1672. J. D. Cassini (MAe, viii, ae SGceueat solange oh 107°2 
1672, Wamecad PT, 1672, 10. 
1719, Bradley and Pound (Genter 8 dace W orter- 
buch, viii, 822), csi u sisal fete is ari eae 10° 
1857, W. C. Bond (Gould, Ast. Jouti vy 58), 26205 end 8°605 
1877. Maxwell Hall (MAS, vol. xliv, p. 121), sin a eR eG 8°789 
1879. Gill ee 1879, vol. xxming pe ABT) 60) san es a 8°78 
1875. Galle, from vibe (ANn, Bd. Ixxxv, s. 267), --..-.. 8"°879 
1877. Lindsay and Gill, from Juno (Dunecht Observatory 
Publications, vol. Hy S11} 5. cae sae es one 8°765 
bean same method has also been applied to Mercury and 
s, but there are great difficulties in the way of obtaining 
pabietantory results from these planets. 
Transits of Venus.—Until quite recently, astronomers hav 
believed that transits of Venus furnish by far the most acoliras 
means of determining the solar parallax. Such transits have 
been observed by three different methods, nam ee 
noting the times of contact between the limbs of Venas and the 
sun. 2. By observing the position of Venus upon the sun’s 
disk with a heliometer. 3. By photographing the sun with 
ig upon its disk, and subsequently measuring the photo- 
graphs, 
Contact observations.—he following are some of the results 
for solar parallax obtained by different astronomers from con- 
peal observations of the transits of Venus in 1761, 1769 and 
