Transactions of The Academy of Science of St. Louis. 



VOL. XI. No. 4. 



THE RELATION OF DIRECT TO REVERSED 

 PHOTOGRArHIC PICTURES. 



FRANCIS E. NIPHER. 



THE SPECIFIC HEAT OF GASEOUS NEBULAE IN 

 GRAVITATIONAL CONTRACTION. 



FRANCIS E. NIPHER. 



Issued June 7, 1901. 



