GENERAL SUMMARY 



OP 



SCIENTIFIC AND INDUSTRIAL PROGRESS 

 DURING THE YEAR 1872. 



The completion of another year imposes upon us the duty 

 of presenting a summary of progress in the sciences, and of 

 their practical applications to the needs and the tastes of 

 mankind. To fulfill the task so as to meet all requirements, 

 to criticise all announcements and discoveries in the various 

 departments of learning, and to select for mention the most 

 important in each, is a task that no one person can accom- 

 plish to the satisfaction of all, in the impossibility of thor- 

 oughly understanding throughout what points are really 

 most noteworthy. The real value, too, of many discoveries 

 is only appreciated after a considerable interval ; and we are 

 likely to overlook, in its apparent insignificance, the germ of 

 some important development, and only realize its character 

 long after the original announcement. If, therefore, some of 

 our readers fail to agree with us as to the comparative value 

 of the selections for a particular subject, both in the prelim- 

 inary summary and in the body of the Record, we can only 

 plead the fallibility of the human intellect in this, as in other 

 instances, and express the hope that we have been more suc- 

 cessful in other directions. 



The most interesting revelations of Astroyiomy continue to 

 be those of the spectroscope. Among the great mass of ob- 

 servations with this instrument which are found in nearly 

 every journal in the world devoted to physical science we 

 may select those of Huggins and Young as examples of 

 what has been done. Our readers may remember that some 

 four years ago Mr. Huggins announced, as the result of 

 spectroscopic observations of great delicacy and difficulty, 

 that the star Sirins was receding from us at the rate of be- 

 tween thirty and forty miles per second. The evidence of 

 this motion was furnished by a displacement of one of the 

 hydrogen lines in the spectrum of the star; but the displace- 



