272 



SCIENCE 



[N. S. Vol. LII. No. 1342 



and Lesley H. Spooner, '03, instructors in 

 neurology and bacteriology, respectively. 



In tte department of chemistry of the West 

 Virginia University the following additions 

 have been made to the teaching stafi: Dr. 0. 

 A. Jacobson, professor; Dr. E. C. H. Davies, 

 associate professor; Lily B. Sefton, assistant 

 professor, and A. E. Owens, instructor. 



New additions to the staff of the division of 

 agricultural biochemistry at the University of 

 Minnesota are: instructors, Arthur K. Ander- 

 son, Paul E. Sharp and G. S. Taylor; assist- 

 ants, Walter E. Hoffman, Earl E. ISTorris, Mar- 

 tin W. Sandstrom, Clifton W. Ackerson and 

 Edward F. Danielson. S. D. Wilkins, special 

 analyst, recently resigned to enter commercial 

 work and his position has been filled by the 

 appointment of Mr. Arnold H. Johnson. 



David E. McEarland, M.S. (Kansas), Ph.D. 

 (Tale), formerly associate professor of indus- 

 trial chemistry and metallurgy at the Univer- 

 sity of Illinois, has been appointed professor 

 and head of the department of metallurg-y in 

 the school of mines of the Pennsylvania State 

 College. 



Dr. Joshua M. Slemons, professor of ob- 

 stetrics and gynecology in Yale University 

 School of Medicine, New Haven, has resigned 

 and is succeeded by Dr. Arthur H. Morse. 

 . Dr. Ardrey W. Downs, formerly assistant 

 professor of physiology at McGill University, 

 Montreal, has accepted the chair of physiology 

 in the University of Alberta. 



Dr. W. S. Lazarus-Barlow has been ap- 

 pointed to the university chair of experimental 

 pathology at Middlesex Hospital Medical 

 School, London. 



DISCUSSION AND CORRESPONDENCE 



GALILEO'S EXPERIMENT FROM THE LEANING 

 TOWER 



To the Editor of Science: Professor Ca- 

 jori's article entitled " Aristotle and Galileo on 

 Palling Bodies "1 recalled to mind a question 

 recently asked by a member of the department 

 of science in this school. The question was: 



1 Science, 60, 615, 1920. 



" Just what experiment did Galileo perform 

 from the leaning tower of Pisa ? " The writer 

 did not know, and endeavored to find out, with- 

 out success. Some notes he made may be of 

 interest. 



Poggendorf, " Geschichte der Physik," p. 

 224, 1879, says " Galileo dropped balls of dif- 

 ferent sizes " and gives no citation of author- 

 ity. 



Rosenberger, "Geschichte der Physik," 1882, 

 Vol. I., p. 141, states that Galileo proved by 

 experiment from the leaning tower of Pisa in 

 1590 that light bodies fall as fast as heavy 

 bodies. No citation. 



The same author in Vol. II., p. 16, states that 

 Galileo let fall stones singly and tied together 

 and they fell in the same time. Also says 

 that Galileo dropped a 100 lb. shot and a J lb. 

 shot and that they reached the ground not the 

 width of a hand apart. No citation. 



Heller, "Geschichte der Physik," Vol. I., p. 

 346, 1882, states that Galileo dropped from the 

 leaning tower of Pisa, pieces of wood, lead and 

 marble and that they fell in nearly the same 

 time. No citation. 



Cajori^ gives a circumstantial account of the 

 celebrated experiment and says, " One morning 

 before the assembled university, he ascended 

 the leaning tower, and allowed a one pound 

 shot and a one hundred pound shot to drop 

 together. The multitude saw the balls start 

 together, fall together, and heard them strike 

 the ground together." No citation. 



Apparently all of the above statements have 

 their foundation in Viviani's " Eacconto Is- 

 torico di Vita di Galileo Galilei," written 

 some time after 1654, at the request of Leopold 

 of Tuscany. Viviani^ states that Galileo dem- 

 onstrated by repeated experiments made from 

 the leaning tower of Pisa that bodies of dif- 

 ferent weights falling through the same 

 medium move with equal velocity. He also 

 states that the experiments were made in the 

 presence of the other readers, philosophers and 

 all the students. Viviani knew Galileo from 



2 ' ' History of Physics, ' ' p. 32, 1899, 



3 ' ' Opere di Gal., ' ' Edizione Nazionale, XIX., 

 p. 606. 



