318 Scientific Intelligence. 



Pritchakk. 8vo. Clarendon Press. Oxford, 1885. — This vol- 

 ume contains the results of Professor Pritchard's measurements 

 during several years past of the light of the stars by the use of 

 the "Wedge Photometer. This instrument is a wedge of very 

 nearly neutral tinted glass six and a half inches long, an inch 

 broad, and 0*145 inch thick at one end, and tapering to - 02 inch 

 at the other. The two places in the wedge at which the light of 

 two stars is extinguished having ,been observed, the distance 

 between them is taken as a direct measure of the difference of the 

 magnitudes of the two stars. The stars selected are those of 

 Argelander's Uranometria Nova. 



The Harvard Photometry was published when the measures 

 for the Uranometria were about three-fourths completed, so that 

 Professor Pritchard has been able to compare his results with 

 Professor Pickering's in the notes. 



The Royal Astronomical Society, of London, has awarded Cop- 

 ley medals to both Professor Pickering and to Professor Pritchard. 



2. Nebulae in the Pleiades. — On the 16th of November Messrs. 

 Paul and Prosper Henry of Paris discovered a nebula close to 

 Maia upon their photograph of the Pleiades. It had a well- 

 marked spiral form and seemed to proceed from the star. It was 

 about 3' in extent. It could not be seen in their telescopes. 



The nebula was, however, afterward seen by M. Struve in the 

 newly mounted 32-inch refractor at Pulkowa. Markings of the 

 same nebula have since been found by Professor Pickering upon 

 a photograph taken by him at the Harvard College Observatory, 

 Nov. 3d. These had been assumed by Professor Pickering to be 

 due to defects in the photographic process, but the irregularities 

 of light correspond so closely to what is described by Messieurs 

 Henry that there can be no doubt as to their origin. The photo- 

 graph also shows markings corresponding to the disputed nebula 

 about Merope. A faint narrow streak proceeds from Electra also. 

 No nebulous light is noticeable about Alcyone, Atlas, Pleione, or 

 Taygeta. 



3. Relation of the Zodiacal Light to Jupiter. — Dr. H. Geel- 

 muyden, of Christiania, in a letter speaks of Professor Searle's 

 researches upon the zodiacal light (see this vol., p. 159). He says : 

 " If the zodiacal matter has the same position among meteoric 

 matter in general as comets of short period among comets, it is to 

 be expected that the fundamental plane of the zodiacal light will 

 have some relation to Jupiter as the principal motor in deflecting 

 the orbits, and therefore in collecting the matter. Now it is 

 worth remarking that the most northerly point of Jupiter's orbit 

 has the heliocentric longitude 188°, or with 60° east elongation 

 178° geocentric longitude; and for matter in the same plane, but 

 nearer the Sun, the approximation to coincidence with 160° is still 

 greater." 



4. Relation of Asteroid Orbits to those of Jupiter. — In Mr. 

 Searle's paper (see this vol., p. 160) it is shown that the asteroid 

 orbits have some relation to the plane of the zodiacal light. These 



