INDUSTRIAL PROGRESS DURING THE YEAR 1875. xxvii 



These asteroids have, when first found, generally appeared 

 as stars of the twelfth or thirteenth magnitudes; whence 

 we may realize the extreme care with which the heavens 

 must be searched by the asteroid hunter. 



It is proposed at the Paris Observatory to institute sys- 

 tematic observations looking to the detection of any intra- 

 mercurial planets. It is intended to photograph the disk 

 of the sun daily, when it is believed the intra -mercurial 

 planets, if any exist, will be observed photographically as 

 thev are crossing;: the disk of the sun. 



The drawings of the appearances of the planets have been 

 undertaken with especial interest. Of these we may men- 

 tion a series made by M. Knobel of twenty-four drawings 

 of Jupiter, and a similar series by Dr. Lohse at Bothkamp. 

 The great equatorial at Washington has also been employed 

 in this field, both by Professor Holden and by Mr. Trouvelot, 

 who is so well known for his beautiful drawings made at 

 Cambridge by the aid of the Harvard College refractor. 

 Terby, of Brussels, is editing the long-lost work of Schroeter 

 on the planet Mars, embracing over two hundred drawings. 



Mr. Todd, formerly of Amherst, Massachusetts, now of the 

 Observatory at Washington, contributes a good series of 

 observations of Jupiter's satellites, extending over four 

 years. Should he be able to continue this series for several 

 years longer at Washington, it will form an important con- 

 tribution to our knowledge of these satellites, and also of the 

 time of the rotation of the earth itself. 



Flammarion has observed and studied carefully the bright- 

 ness and color of Jupiter's satellites. Schmidt and Heis have 

 published in full their observations of the Zodiacal Light. 

 It is to be hoped that the observations of Rev. J. Jones may 

 also one day see the light. 



Gylden's method of computing the special perturbations 

 of the asteroids has been applied by Boeklund to the prep- 

 aration of tables of the movements of the asteroid Iphi- 

 genia. 



Comets and Meteors. During 1875 we have received no 

 announcement of the discovery of any new comet; but two 

 well-known and exceedingly faint periodical comets have 

 been observed a few times. The record for the year is 

 therefore 



