The Astrophysical Observatory 4 2 9 



which, in its terrestrial manifestations, is the principal object 

 of our study, it has long been well known that the spectro- 

 scope could recognize only about one-quarter; three-quar- 

 ters of all this solar heat being in a form which the ordinary 

 spectroscope cannot see nor analyze, lying as it does in 

 the almost unknown ' infra-red ' end of the spectrum, where 

 neither the eye nor the photograph can examine it. It has 

 been known for many years that it was there, and we have 

 had a rough idea of its amount, with an almost total incapac- 

 ity to exhibit it in detail. Our imperfect knowledge of this 

 region is at present represented by a few inadequate types 

 of parts of it given in drawings made by hand, where the 

 attempts to depict it at all are even to-day more crude than 

 the very earliest charts of the visible spectrum made in the 

 infancy of spectroscopic science. 



" One of the first pieces of work which this observatory has 

 undertaken is to explore and describe what may be properly 

 called 'this great unknown region,' by a method which the 

 writer has recently been able to bring to such a degree of suc- 

 cess as to give good grounds for its continued prosecution 

 and for the hope that a complete map of this whole region 

 will shortly be produced by an automatic, and therefore trust- 

 worthy, process, showing the lines corresponding to the so- 

 called Fraunhofer lines in the upper spectrum." 



It is now well understood that nearly every movement 

 which goes on within the confines of this planet, not only 

 from changes of the seasons or of rain, or the movement of 

 wind, or storm, but every manifestation of life from that of 

 the lowest vegetable form, up through animal existence, to 

 that of man, including all his works and industries, comes 

 from the sun, so that man himself and all his works are, in 

 a physical sense, strictly its product. 



It is known in some cases to what these effects are traced, 

 in the greater number we are still ignorant, but in all cases 



we know that a something we call " energy " comes across the 

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