CONTENTS 

 Original Papers 



Page 

 Mathematics. — Strains due to temperature gradients, with special reference 



to optical glass. KRSEaNE D. Williamson 209 



Astronomy. — Modern theories of the spiral nebulae. HebER D. Curtis 217 



Abstracts 



Geology 228 



Entomology / 229 



Paleontology 229 



Navigation 231 



Proceedings 



Washington Academy of Sciences 234 



Biological Society 234 



Scientific Notes and News 239 



