634 



SCIENGE. 



[N. S. Vol. VIII. No. 201. 



responding figures for October 25, 1897, are 

 also given : 



1887 1898 



Literary department 1276 1254 



Engineering department 269 245 



Medical department 425 407 



Law department 710 713 



Dental department 218 230 



Homceopathic department 59 60 



Pharmaceutical department 76 73 



■3033 2982 



The attendance in Oberlin College shows a 

 falling off of nearly one hundred, the figures to 

 date being 1,040 as compared to 1,135 last year. 

 The increase in tuition may account for part of 

 the loss. Tuition now is placed at S75.00 per 

 year. 



De. John Guiteeas, professor of pathology 

 in the University of Pennsylvania, will resign 

 at the close of the present year to accept the 

 chair of the practice of medicine at the Univer- 

 sity of Havana. Dr. Guiteras has been greatly 

 interested in the liberation of Cuba and wishes 

 to build up the medical courses in the Univer- 

 sity of Havana. 



C. E. Mendenhall, Ph.D. (Johns Hopkins), 

 has been appointed instructor in physics in 

 Williams College. Dr. J. C. Hardy has been 

 appointed instructor in mathematics in the same 

 institution. 



Thos. Clarke, B. S. (University of N. 

 C, '96), Ph.D. (Bonn, '98), has been appointed 

 assistant in chemistry at the University of 

 North Carolina. 



Among foreign appointments we note that 

 Dr. Frentzel has been promoted to a professor- 

 ship in the Agricultural College at Berlin and 

 Professor Wiilsch to a professorship of mathe- 

 matics in the Technical Institute at Briinn. Dr. 

 H. E. Ziegler, of Freiburg, i.B. , has been ap- 

 pointed successor of Professor Kiickenthals, 

 'Kitter ' professor of phylogeny in the Univer- 

 sity at Jena ; Dr. E. Eeinbach, of Berlin, pro- 

 fessor in the Chemical Institute at Bonn, and 

 Dr. Fenner, of Ais, professor of geodesy in 

 the Technical Institute at Darmstadt. At Vi- 

 enna, Dr. Zukal has been made professor of 

 . phytopathology in the Agricultural College, and 

 Dr. Kitter Lorenz V. Liburnau has qualified as 



decent in zoology ; in the University Dr. Wer- 

 ner has qualified as decent in zoology, and Dr. 

 Keithoffer in technical electricity. 



DISCUSSION AND CORRESPONDENCE. 

 MEASUREMENTS OF PRECISION. 



An article in the Physical Review, September- 

 October, 1898, by S. N. Taylor, should not be 

 overlooked by those who are interested in 

 knowing the degree of precision which may be 

 reached in linear and other measurements. 



The paper itself should be consulted, but a 

 few of Mr. Taylor's most remarkable accom- 

 plishments may be mentioned here. It comes 

 in his way to measure several diameters of a 

 coil of wire, consisting of fifteen layers, with 

 fifteen turns in each layer, the mean diameter 

 of the coil being about 20 cm., and the wire 

 being No. 18, copper, double-silk insulated, pass- 

 ing through a bath of hot paraffine during the pro- 

 cess of winding. 



It is wound upon a cup-shaped cylinder of 

 plaster of Paris, which was soaked in a mixture 

 of linseed oil and liquid dryer sometime before 

 its use. Mr. Taylor tabulates his measure- 

 ments of these diameters, each layer, as it is 

 wound on, in figures carried to thousandths and 

 ten thousandths of a millimeter, thus implying that 

 his measures are made to one part in two 

 millions. 



They are made, he says, by means of a cathe- 

 tometer, before which the coil is mounted on 

 an axis, that it may be turned into six different 

 positions. Unfortunately, he does not say how 

 far the coil was from the cathetometer, or give 

 the name of the maker of an instrument of a 

 type so extraordinary as to justify these figures 

 on the diameters of a wire coil. Still more un- 

 fortunatel}', he fails to give the results of several 

 independent measurements in each position, 

 which he says were taken. 



A thousandth of a millimeter is always worth 

 struggling for, and, as a variation of a single 

 degree in the temperature of his cathetometer 

 bar would probably change its length by 15 or 

 20 of them, it is to be inferred that highly per- 

 fected methods of determining that temperature 

 were used, although the author is also silent on 

 that point. The level on the cathetometer 



