52 BULLETIN OF THE 



ings on a large scale were obtained of, 1st, the planet Saturn,' 

 2d, of the central portion of the nebula of Orion; and 3d, of 

 the Horse-Shoe Nebula (G. C. 4403). The scale of the 1st is 

 about 12 inches to 18" ; of the 2d, 1 inch to 32" ; of the 3d, 1 

 inch to 129". 3. Of these, the 2d and 3d were exhibited to the 

 Society. The drawings contain only what was seen certainly, 

 there being no conjectures recorded ; and that of the Horse-Shoe 

 Nebula is almost entirely satisfactory. The nebula of Orion, 

 however, must be regarded as a preliminary sketch, as this 

 object is much too complicated for satisfactory representation in 

 the limited time at the disposal of Mr. Trouvelot. It will be 

 corrected during the next opposition. 



The method pursued in making the drawing of the nebula 

 (G. C. 4403) consisted in putting in the stars in the neighbor- 

 hood of the nebula by means of a glass reticle ruled into squares. 

 The sides of the squares were about 1' of arc. The entire 

 number of stars was put in in one night's work. Mr. Holden 

 has determined the average error of a star-position, in this- 

 nebula, to be about 1".T in R. A., and 5". 3 in Declination, 

 by comparison of 11 of Mr. Trouvelot's star-positions with 

 11 of Lassell's (Mem. R. A. S., vol. xxxvi. p. 49). The larger 

 residual in R. A. is accounted for by the fact that the driving- 

 clock of the equatorial was not performing well. This average 

 error of a star-position would not be appreciable in any drawing 

 of the nebula which could be put on an ordinary quarto page. 

 The stars of the Nebula Orionis were put in from G. P. Bond's 

 catalogue. 



Mr. Holden verified most of the details of the drawings — 

 especially in the brighter parts of the Horse-Shoe Nebula, where 

 variation of form may be suspected — and was able to declare 

 the pastel drawing to be very nearly correct, not only in gene- 

 ral effect, but as to the important details. A decided difference 

 exists between some of the previous drawings and this one in the 

 neighborhood of Lassell's star No. 1. At present, the brightest 

 nebulosity /b/Zows this star. LXssell, Mason, and others have 

 drawn it preceding. The great merit of pastel drawings for this 

 kind of delineation is that changes can easily be made, and that 

 the effect of nebulous matter can be successfully reproduced. 



Remarks were made by Messrs. Coffin and Taylor. 



Mr. E. B. Elliott read the following paper on 



MUTUAL RELATION AS TO PRICE OF GOLD, GREENBACKS, SILVER 

 BULLION, AND SILVER COIN. 



Gold Price of Silver Bullion. — Owing to the large demand 

 for gold, and the corresponding diminution in the demand for 



