34 CARNEGIE INSTITUTION OF WASHINGTON. 



tory action is accurately determind; and an automatic temperature register 

 which will give a continuous record of temperature changes in the calorim- 

 eters to which it is applied. 



Along with the work carried on at the new laboratory, computations of 

 additional results of experiments, previously executed in the laboratory of 

 Wesleyan University, have been continued. A volume giving an account of 

 these experiments on respiratory exchange and energy transformation in man 

 is now in press as publication No. 123. In connection with these earlier 

 researches, it has been shown, among other interesting facts, that in muscu- 

 lar work man attains about the same mechanical efficiency as the recently 

 developt internal-combustion engine. 



The achievments already attaind in the development of novel methods and 



effectiv apparatus for studies of the sun, and the additions to our knowledge 



of solar physics already made at this observatory, not only 



The Solar justify the predictions of its founders but warrant the 



Observatory. ..-.,, . •, • 



anticipation of still more important contributions to astro- 

 physics in the near future. Work of investigation and work of construction 

 have proceeded simultaneously during the year, both at the observatory site 

 on Mount Wilson and at the shops and physical laboratory in Pasadena. 



The 60-inch equatorial reflecting telescope, whose installation was com- 

 pleted a year ago, has been tested during the past year and proved to be of 

 unequald excellence, whether used as a visual or as a fotografic instrument. 

 Its optical perfection and its wide range of applicability make it a note- 

 worthy contribution to progress in observational astronomy. The 150- foot 

 tower telescope, authorizd by the budget of the current year, is in a for- 

 ward state of construction and will soon become one of the most eflfectiv 

 units in the telescope battery of the observatory. 



The capital discovery of the existence of the Zeeman effect in the sun, 

 announced by the Director a year and a half ago, has been confirmd and 

 extended in its application to further interpretation of the nature of sun- 

 spots, as well as to researches into the more recondite electromagnetic prop- 

 erties shown by the sun. Closely connected, apparently, with these properties 

 are the major and minor "magnetic storms" to which the earth's magnetism 

 is subject, now of special interest alike to the staff of the Solar Observatory 

 and to the staff of the Department of Terrestrial Magnetism. Approaching 

 the observd phenomena from different points of view, the cooperation of 

 these two departments can hardly fail to secure distinct advances in this 

 fruitful field of research. Indeed, in general, the work of the Solar Observa- 

 tory may be considerd as important to terrestrial physics as it is to solar 

 physics. 



The report of the Director gives a summary of the more important results 

 accomplisht to date in his studies of the sun, an account of the experiments 



