70 TRANSACTIONS OF THE [JAN. 7, 
Publication XIV.). For most of the best catalogues these sys- 
tematic corrections were taken from Auwers’ paper in Astron. 
Nach. 3196; for others it was taken from Boss’ paper on De- 
clinations of Fixed Stars, and corrected by a quantity (the re- 
sult of special research), which would convert Boss’ corrections 
from the Boss-system to the A. G. C.system. For several other 
catalogues not included in either of these lists a systematic cor- 
rection was independently deduced from the observations them- 
selves in a manner similar to that pursued by Auwers. With 
the data thus found the declination and the proper motion were 
deduced by the method of least squares, and from the residuals 
then found by substitution in the equations of condition probable 
errors of both declination and proper motion were computed by 
the usual formule. The average probable error of the declina- 
tion reduced to 1875 for the fifty six stars is thus found to be 
0.095 with an average weight of 354, determined by an average of 
236 observations ; and for proper motion likewise the average 
probable error is 0.’0035 with an average weight of 17,020. 
These results appear to compare very favorably with work of 
the same kind done elsewhere, and give the position of these 
stars such a precision as will make the absolute latitude-formula 
for Columbia College Observatory very accurate, and as will 
also give astronomers here and elsewhere fifty-six more funda- 
mental points of reference in the northern heavens. 
The second paper was by Prof. A. M. Mayer, “ On Chladni’s 
figures formed on vibrating plates strewn with sand ;” with ex- 
periments showing the method of obtaining these figures; and 
the exhibition of the figures in sand transferred to paper by a 
process inyented by Prof. Mayer; also the comparison of the 
real figures with those given by the Physico-Mathematical in- 
vestigations of Lord Rayleigh and with those given in text- 
books on Physics. 
The paper was not intended for publication, and after discus- 
sion the Academy adjourned. 
J. F. Kemp, 
Recording Secretary. 
