REPORT OF THE SECRETARY. 5 



This condition is especially insisted on, because the credit thus required 

 is an important evidence to the world of the proper management of the 

 Smithson fund. 



Publications in 1873. — During the past year the eighteenth volume of 

 the quarto series of the Smithsonian Contributions to Knowledge has 

 been published. The several parts of this volume have been described 

 in previous reports. It contains the following papers : 



I. Tables and results of the precipitation in rain and snow in the 

 United States, and at some stations in adjacent parts of North America, 

 and in Central and South America. Collected by "the Smithsonian Insti- 

 tution, and discussed under direction of Joseph Henry, Secretary. By 

 Charles A. Schott, 4to., pp. 178, eight diagrams, five plates and three 

 charts. 



II. Memoir on the secular variations of the elements of the orbits of 

 the eight principal planets, Mercury, Venus, the Earth, Mars, Jupiter, 

 Saturn, Uranus, and Neptune, with tables of the same. Together with 

 the obliquity of the ecliptic, and the precession of the equinoxes in both 

 longitude and right ascension. By John N. Stockwell, M. A., 4to., pp. 

 214. 



III. Observations on terrestrial magnetism and on the deviations of 

 the compasses of the United States iron-clad Monadnock during her 

 cruise from Philadelphia to San Francisco, in 1805 and 1866. By Win. 

 Harkness, M. D., 4to., pp. 225, with two diagrams. 



IV. Converging series expressing the ratio between the diameter and 

 the circumference of a circle. By William Ferrel, 4to., pp. 6. 



This volume consists of 643 pages, and is illustrated by five plates, three 

 large double charts, and numerous diagrams. The distribution of this 

 volume to foreign societies has been nearly completed. As in the case 

 of the preceding volumes, it will tend to perpetuate the name of Smith- 

 son conspicuously in the records of the history of science, and will thus 

 form a more befitting monument to his memory than one of marble or 

 of bronze. 



One of the memoirs accepted for future publication in the Contributions 

 is on the Lucernaria, by Professor Henry J. Clark. This memoir relates to 

 a class of animals which are more or less octagonal, bell-shaped, or rather 

 inverted umbrella-like, with tentacles clustered in groups at the eight 

 angles. They were in former times regarded as a group of the polyps, 

 that is, related to the sea-anemones, but in more recent times have been 

 associated with the Acalephs or sea-nettles and jelly-fishes, and either 

 combined with one of the more comprehensive orders, or regarded as 

 the representatives of a peculiar one. Such is the group which has 

 been the subject of Professor Clark's latest studies, and which is con- 

 sidered by him as entitled to ordinal rank in the class of Acalephs. 



His work is divided into two parts 5 the first devoted to the "general 

 and comparative morphology," and the second restricted to the "anatomy 



