1881.J 603 [Chr.se. 



This value of nz differs by less than -^^ of one per cent, from the mean 

 of various mechanical estimates, which was given in Note 15. 



153. Linear Harmonies. 



The harmonies to which Schuster refers, in the third conclusion of liis 

 summary, seem to he linear rather than geometric. If w^e omit the speci- 

 ally phyliotactic lines C and 7i, together with the secondary lines of the D 

 and h groups, the percentages of the geometric, Schelleu and Gibbs tables 

 give the following coincidences qf harmonic tendency : 



The only instances in Avhicli the deviations from exact harmony exceed \ 

 of the right hand unit, are the G line in the geometric table, the A and E 

 lines of ScLelleu, and the A line of Gibbs. 



154. Interstellar Phyllotaxy. 



The interstellar abscissas, Note 46, present the following phyliotactic 

 features : 



1. The determination of the paraboloid requires 3 abscissas. 



2. The whole number of abscissas, between the vertex and the stellar 

 region, is 3x13. 



3. The abscissas between Aj and Agg are divided into two groups, each 

 group containing 2x3^ abscissas. 



4. Each group has two equal subdivisions ; the inner representing ten- 

 dencies to condensation, the outer giving no present evidence of such ten- 

 dency, except in comets, meteors and possibly asteroids. 



155. Distance of a Centauri and its connection witJi tlie Interstellar Para- 

 boloid. 



Newcomb gives estimates of the parallax of o. Cent(iuri. ranging between 

 0".48 and 1".96. The mean of Henderson's observations, in 1832-3, as 

 deduced b}'' himself, was 1''.16 ± .11. Peters, from the same observa- 

 tions, found 1". 14 ± .11. Henderson obtained 0".913 from Maclear's obser- 

 vations in 1839-40 ; Peters, 0'''.976 zb .064 from the same ; Maclear, 0".919 

 ± .034 from declinations in 1842, 1844 and 1848 ; Moesta, 0".880 ± .068 

 from declinations in 1860-4. There is, therefore, an uncertainty as to the 



PEOC. AMER.PHILOS. SOC. XIX. 109. 3x. PRINTED DEC. 31, 1881. 



