APRIL 19, 1921 abstracts: astronomy 189 



the form and indument of its leaves, the size and color of its flowers, and the 

 size and form of its fruit. Dr. Rose, who collected both species, refers to this 

 species in his field notes, as follows: "Brugmansia sp. — Flowers of a saffron 

 yellow; corolla lobes acuminate, reflexed; calyx 3-lobed, green: flowers smaller, 

 throat relatively broader, and calyx lobes more attenuate than in the red- 

 flowered species collected at Ambato; the leaves are also relatively broader, 

 and are distinctly lobed, or angular-toothed, and tomentose. 



ABSTRACTS 



Authors of scientific papers are requested to see that abstracts, preferably prepared 

 and signed by themselves, are forwarded promptly to the editors. The abstracts should 

 conform in length and general style to those appearing in this issue. 



ASTRONOMY.^ — Results of observations with the nine-inch transit circle, 1903- 

 1911. W. S. Hichelberger and H. R. Morgant. Publ. U. S. Naval 

 Observatory, II. 9^ Pp. 920. 1921. 



This publication contains the results and discussions of 49,437 observations 

 of the sun, moon, planets and 4,526 standard stars made with the 9-inch 

 transit circle of the U. S. Naval Observatory. 



The following new equipment was used in the work: a self-winding clock 

 kept at almost constant temperature and pressure, the hourly rate of which 

 is known within 0.001 sec; a personal equation machine for determining the 

 personal equations of observers in observing stars at all declinations and in 

 observing the sun, moon, and planets; a high-power microscope for deter- 

 mining the forms of the pivots ; and a screen system for partially eliminating the 

 magnitude equation of the observer. Extensive determinations were made 

 of the forms of the new pivots; of the errors of each of the 10,800 divisions 

 of the recently graduated circle; of the flexure of the instrument; of the errors 

 of the new micrometer screws; and of the positions of the two meridian marks. 

 The personal equations of the observers, both in right ascension and declina- 

 tion, were derived from extensive inter-comparisons of the observations in 

 connection with the results from the personal equation machine. 



From the discussion of 4,000 circumpolar observations it was found that 

 the refractions given by the Pulkowa Tables require a correction of 

 -0".134 tan z to satisfy the observations under the conditions under which 

 they were taken at Washington. A comparison of the observations of 2,800 

 zodiacal stars made at Cape of Good Hope and at Washington confirmed this 

 result. The variation of the refraction for different hours of the night and 

 different times of the year was found negligible. The latitute of the Ob- 

 ser\-ator}^ deduced from this discussion is +38° 55' 14 ".34. 



From 7,000 observations, made on 410 nights, new and accurate positions 

 were determined for the clock stars, and these positions were used in 

 forming the clock corrections for the reduction of the work. The positions 

 of the pole stars used in the azimuth reduction were determined, also indepen- 

 dently of any other positions, from observations above and below pole. The 

 discussion of the observations of the sun and moon gave a correction of 

 -0.03 sec. to the equinox, and -0".4 to the obliquity of the ecliptic, as 



