440 



PIONEERS OF SCIENCE IN AMERICA. 



conclusions and suggestions that he had derived from these 

 data. The document was printed, making a large octavo 

 volume. 



As the preparations for opening the college were not yet 

 complete, Prof. Bache offered his services gratuitously to reor- 

 ganize the public schools of Philadelphia, and his offer was 

 gladly accepted by the municipal authorities. A year later, 

 finding that the trustees of the college were still unprepared to 

 open the institution, he relinquished the salary of his office and 

 accepted from the city a much smaller compensation for his 

 time. His work on the public schools was completed in 1842, 

 and resulted in a system that has been taken as a model by 

 other cities in various parts of the United States. So highly 

 were his labours appreciated that the Central High School was 

 frequently called Bache Institute. 



Girard College having made very little progress, he now 

 resigned all connection with it, and accepted his former chair 

 at the University of Pennsylvania, with its welcome opportuni- 

 ties for scientific research. The preceding six years had by no 

 means been a blank with respect to his favourite investigations. 

 When he went to Europe he took care to provide himself with 

 a set of portable instruments, with which, as a relief from the 

 labours imposed by the special object of his mission, he made a 

 connected series of observations on the dip and intensity of 

 terrestrial magnetism at important places on the Continent and 

 in Great Britain. 



After his return to Philadelphia he co-operated in the under- 

 taking of the British Association to determine by contemporane- 

 ous observations at widely separated points the fluctuations of 

 the magnetic and meteorological elements of the globe. He 

 also made in his summer vacations a magnetic survey of Penn- 

 sylvania. Mr. Cramp, afterward the famous shipbuilder, was 

 then a boy 'in the high school, and assisted Prof. Bache in his 

 observations. 



Valuable instruments and methods for performing scientific 

 observations were devised by Bache during this period. He 

 invented an ingenious instrument for determining the dew 

 point, which is especially valuable where readings must be 

 made by persons without special scientific training. Only 

 much later did he learn that the principle of the device had 

 already been used by Belli, of Milan. He also introduced a 



