136 THE MICHIGAN ACADEMY OF SCIENCE. 



PKOBLEMS IN TERRESTRIAL PHYSICS, INCLUDING THE 



EARTH'S ROTATION. 



HENRY B. BAKER. 



Quite a number of diseases are quantitatively related to meteorologi- 

 cal conditions. Apparently such conditions to a very great degree con- 

 trol the extent of th^ir prevalence. This has been certainly known since 

 the days of Hippocrates, yet slow progress ha^ been made in working 

 out practical measures for the lessening of such diseases. Certain dis- 

 eases and conditions of pain connected with the brain and nervous sys- 

 tem are, to a considerable extent, contributed to b}- atmospheric press- 

 ure. A study of the subject for several years- has convinced me that a 

 large proportion of all suicides occur in the early morning hours, when 

 or immediately after the time when the atmospheric pressure is low, 

 and when, therefore, the blood supply to the brain and nerves is defi- 

 cient ; because the surface of the body is several square feet in area, 

 and the variation in pressure upon it is as much as eight pounds on every 

 square foot. 



This brief glance at this side of the subject may serve to indicate the 

 fact that meteorology can contribute greatly to the advancement of san- 

 itary science. 



The question has occurred to me whether it is possible for a student 

 of meteorology for health purposes to contribute something reciprocally 

 for the advancement of meteorological science. If this attempt is suc- 

 cessful in any degTce it will probably be so through new modes of group- 

 ing the facts presented, especially by graphic diagrams which seem to 

 put new meaning into facts established many years ago. 



One question around which it may be convenient to group what I now 

 have to offer is "What Makes the World Go 'Round?" 



A satisfactory' answer to this question I do not remember to have ever 

 seen or heard ; yet, from time to time for many years my attention has 

 been attracted to certain natural phenomena, studied for their relations 

 to the public health, which have seemed to me to satisfactorily answer 

 this question, and also a few other questions to which this one is 

 correlated. 



The attractive force tending to take this earth toward the sun has 

 long been understood, but the repelling force has not been much dwelt 

 upon. Yet, that radiant energy is given off from the sun is one of the 

 most common ideas. How that radiant energy acts, in conjunction with 

 force derived from the earth's attraction, to cause the earth's rotation, 

 it is one of the purposes of this paper to suggest. 



We now know that the atmosphere obeys many of the same laws which 

 govern the natural movements of water, that it flows in directions of least 

 resistance, that is, — toward areas of low pressure from areas of high 

 pressure. Stating the facts in other terms, it is well known to meteor- 

 ologists that the wind is caused by difference in the weight of the atmos- 

 phere in different parts of the world, the air moving from areas of great 



