456 POPULAR SCIENCE MONTHLY. 



Lindsay is carrying ont a similar plan of sociological excursions 

 at the university. Regular trips are made to the large business 

 establishments, and to the various charitable and reformatory in- 

 stitutions, slum districts, etc. A thorough investigation of the 

 condition of the colored population of Philadelphia is contemplated 

 in the near future. An assistant in sociology is to be appointed 

 for next year, whose special work will be an investigation of the 

 negro, Italian, and other foreign population. The College Settle- 

 ment Association of Philadelphia will co-operate with the uni- 

 versity in this work, by furnishing an assistant in carrying on 

 the proposed investigation. 



An important contribution to science has recently been made 

 by Dr. George E. Fisher and Dr. Isaac J. Schwatt, of the mathe- 

 matical department of the university, in their translation into 

 English of Durege's Elements of the Theory of Functions. Dr. 

 Schwatt has also written A Geometrical Treatment of Curves 

 which are Isogonal Conjugate to a Straight Line. This work 

 called forth the following commendation from the eminent French 

 mathematician Vigarie : " The work has been admirably conceived, 

 and in my belief it is the first essay of the kind that has ever been 

 published." 



As early as 1775 David Rittenhouse, sometime vice-provost, 

 published an oration on astronomy, but wrought more than he 

 wrote. The erection of an astronomical observatory as a depart- 

 ment of the university has been an unfulfilled desire until the 

 present. In 1876, Reese Wall Flower, of Delaware County, Penn- 

 sylvania, bequeathed to the university a large sum of money for 

 the erection of an astronomical observatory. Among the assets 

 turned in to the university as a part of this sum was the farm in 

 Delaware County known as the Flower farm. It happily offered 

 the most available site for the observatory, the erection of which 

 is now under way. The observatory buildings, three in number, 

 consist of the equatorial building, the meridian building, and the 

 residence of the director, Prof. Charles L. Doolittle, late of the 

 ' Lehigh University. The principal instruments comprising the 

 equipment are an equatorial of eighteen-inch aperture, with spec- 

 troscope ; a meridian circle and a zenith telescope ; and a three- 

 inch universal transit. Graduate students in astronomy will be 

 instructed in the details of observatory practice, and will be ex- 

 pected to participate in the regular work. The outlined plan 

 contemplates systematic observation of comets and small planets, 

 investigation of various latitudes, and spectroscopy. A small ob- 

 servatory for the convenience of undergraduate students will also 

 be erected in the Botanical Garden on the university grounds, 

 thus making the large observatory free for advanced work. 



The John Harrison Laboratory of Chemistry, recently added 



