SCIENCE. 



291 



AN IMPROVED METHOD OF OPERATING THE 



SPRENGEL AIR-PUMP.* 



By Professor Ogden N. Rood. 



Professor Rood's paper gave an account of his 

 experiments with the pump for the purpose of obtaining 

 the highest possible vacua. He first experimented with an 

 arrangement similar to the ordinary form of the Sprengel 

 pump, and reduced the pressure to one three-millionth. 

 The exhaustion went on very rapidly at first and then 

 very slowly — slower than the increased rarefaction 

 seemed to call for. This indicated a leakage, and it was 

 found that this leakage amounted in or.e minute to one- 

 eighty-seven millionth of an atmosphere. The form of 

 the pump was modified to correct the leakage, and a 

 vacuum was obtained with a pressure of one-sixty- 

 mi lionth. It was impossible to get beyoDd that point, 

 and it occurred to Professor Rood that the potash he 

 used might have given out moisture. He therefore sub- 

 stituted sodium, and the pressure rose only to one-four- 

 millionth. Anhydrous phosphoric acid was substituted 

 for the sodium, and the pressure fell to one-millionth. 

 It finally struck the experimenter that the trouble was in 

 the gauge, and when a correction was applied to the 

 gauge, vacua were obtained with pressures of oneninet}- 

 lour-millionth and one- hundred - and - ten - millionth. 

 Higher vacua even can be obtained. 



It had recently been stated in Nature, said Professor 

 Rcod, that his airangement was exhibited four years ago 

 at the Kensington Garden, and he would not, therefore, 

 call it new. But the best result obtained in England was 

 one-twenty-millionth, and the best result reached by an 

 eminent French chemist was one-seventeen-millionth. 

 He, therefore, thought there must be at least something 

 new in his method of using the Sprengel air-pump. 



REPORT OF THE COMMISSIONER OF EDUCA- 

 TION, FOR 1878. 

 {Extracts.) 

 TEXT-BOOKS AND COURSES OF STUDY. 



The lack of uniformity in the conditions of public edu- 

 cation in the different States is illustrated in the report on 

 text-books and courses of study. 



Returns from 31 States present the following informa- 

 tion : 



The State board is empowered to decide these matters in 

 California, Connecticut, Delaware, Louisiana, Nevada, and 

 Oregon. In Kansas, Nebiaska, New York, and Rhode 

 Island, the State superintendent or commissioner has au- 

 thority to recommend the text-books to be used, but their 

 adoption and the course of study are finally decided by the 

 school committee or district boards. In Iowa and South 

 Carolina these matters have been decided by a commission 

 appointed for the purpose. In Maine, authority in these 

 matters is delegated to the town supervisor or school com- 

 mittee ; in Maryland, to the county commissioners ; in 

 Massachusetts, to the school committee ; in New Jersey, to 

 school trustees of districts acting with the county superin- 

 tendents ; and in Pennsylvania, to the directors and con- 

 trollers of each school district, acting with the teachers. 

 District or local boards either solely or acting in concert 

 with superintendents and teachers decide these matters in 

 Michigan, Mississippi, Missouri, Ohio, and Wisconsin. 



In the following Slates — Minnesota, New Hampshire, 

 Tennessee, Texas, Virginia, and West Virginia — the course 

 of study is prescribed by law, but in the application discre- 

 tion is given to superintendents, local boards, teachers, &c. 



In Indiana, North Carolina, and Vermont no definite pro- 

 vision with reference to these matters has been made. 



UNIVERSITIES AND COLLEGES. 



The total number of universities and colleges reported is 

 358, with 3,885 instructors and 57,987 pupils. In the pre- 

 paratory departments of these institutions were 682 instruc- 



* Read before the National Academy of Sciences, N. Y., 1880. 



tors and 26,266 students ; in the collegiate departments, 

 3,203 instructors and 30,368 students: unclassified, 1,353. 

 They had 2,187,932 volumes in their libraries, and the value 

 of their buildings, grounds, and apparatus was $36,871,213 ; 

 their productive funds, $37,071,958 ; income from these 

 funds, $2,548,324; receipts from tuition, $1,555,484; re- 

 ceipts from State appropriations, $622,577 ; aggregate 

 amount of scholarship funds, $1,719,426. 



Of the students in the preparatory departments, 18,481 are 

 males and 6779 females ; 6,576 are preparing for a classical 

 course and 5,621 for a scientific course. In the collegiate 

 departments, 15,803 (14,152 males and 1,651 females) are in 

 classical course, and 3,893 (2,724 males and 1,169 females) 

 are in scientific course. 



The summary of college entrance examinations gives the 

 following facts : Total number of candidates, 5,297 ; ad- 

 mitted without conditions, 2,553 \ conditioned in Latin, 

 822 ; in Greek, 577 ; in mathematics, 1,068 ; in history and 

 geography, 585 ; rejected for deficiency in Latin, 84 ; in 

 Greek, 70 ; in mathematics, 66 ; in history and geography, 

 22 ; in two or more subjects of examination, 424. 



There are also statements of the numbers preparing for 

 college, classical, and scientific courses, as follows : num- 

 ber preparing for classical course in academies, 6,206 ; in 

 preparatory schools, 4,195 ; in universities and colleges, 

 6,576 ; preparing for scientific course : in academies, 2,167 > 

 in preparatory schools, 1,107 > i n universities and colleges, 

 5,621 ; in preparatory departments of scientific schools, 

 1,550 ; total, 27,422. 



Students in institutions for superior instruction are dis- 

 tributed thus, viz.: in colleges, 30,368 ; in schools of 

 science, 11,603 ! i n schools for the superior instruction of 

 women, 18,115 ; in all 60,086. 



The Commissioner presents a brief outline of the move- 

 ment in colleges to satisfy the demand that the study of 

 science and sociology be advanced to an equality with the 

 classics and mathematics. Without sacrificing anything of 

 the former curriculum, temporary provision for the new 

 studies has been made in most instances by a system of 

 electives. The action is traced through the record of Har- 

 vard and Yale Colleges, and the views of Dr. McCosh, 

 president of Princeton College, Dr. Peabody, of Harvard 

 University, and Prof. B. L. Gildersleeve, of Johns Hopkins 

 University, with reference to the most important conditions 

 of the change, are cited. 



Some have feared that in this readjustment of college 

 courses the classics would be sacrificed, but the present 

 tendency is toward greater thoroughness and a more ex- 

 tended range in classical studies ; nor under the elective 

 system is the number of students who take the modern in 

 place of the classical course sufficiently large to create any 

 apprehension as to the future influence of classical study. 



The prevalent views on this subject are well represented 

 in letters from Professor Haeckel of Jena and Professor 

 Zarncke of Leipzig, which are given in full in the report. 



SCHOOLS OF SCIENCE. 



Of this class 76 schools, including the United States 

 Naval and Military Academies, were reported to the 

 Bureau. They numbered 809 instructors and 13,153 stud- 

 ents. The comparative table for the years from 1870 to 

 1878, inclusive, shows this to be an increase in all particu- 

 lars over the figures reported for any previous year. The 

 increase above 1877 was in number of schools, 2 ; instruc- 

 tors, 28 ; students, 4,594. The number of students in pre- 

 paratory departments was 1,436, viz.: 1,153 males and 283 

 females ; the number in scientific departments was in reg- 

 ular course, 4,806; in partial course, 772 ; number of grad- 

 uate students, 97. The number of volumes in general 

 libraries was 119,164, an increase in the last school year of 

 3,543 ; the number in society libraries was 7,737. The 

 value of grounds, buildings, and apparatus reported, was 

 $7,587,421 ; productive funds, $5,020,446 ; income from 

 the same, $319,503; receipts from tuition fees, $68,660; 

 from State appropriations, $484,742. 



With reference to schools of science the Commissioner 

 observes : 



" By the act of 1862 donating public lands to the several 

 States and Territories which should provide colleges for the 

 benefit of agriculture and the mechanic arts, the movement 



