The Period from i8(h to 1870 19 



Although scientists have cooperated in investigating the problem of the 

 causes of glaciation during the 70 years since Foster's address, they have 

 not yet reached a generally accepted explanation of the successive periods 

 of glaciation that the middle latitudes of the earth have experienced. 



Papers of Interest Presented at the Meetings 



The Buffalo, N. Y., Meeting, August, 1866. ( J'ol. 75) 



1. On the Theory of Meteors. Daniel Kirk wood. 



2. On the Physical Condition of the Sun's Surface and the Motion of 

 the Solar Spots. Elias Loomis. 



The Burlington, J't., Meeting, August, 186/. (Vol. 16) 



1. Observations of Venus near Inferior Conjunction. C. S. Lyman. 



2. On the Periodicity of the Aurora Borealis. Joseph Lovering. 



3. Considerations Relating to the Climate of the Glacial Epoch in North 

 America. Edward Hungerford. 



i &* 



The Chicago Meeting, August, 1868. (Vol. if) 



1. The Nature of Electric Discharge. O. N. Stoddard. 



2. On Hansen's Theory of the Physical Constitution of the Moon. Simon 

 Newcomb. 



3. On the Source of Free Hydrochloric Acid in the Gastric Juice. E. N. 

 Horsford. 



The Salem; Mass., Meeting, August, icS'do. {Vol. 18) 



1. Spectrum Observations at Burlington, Iowa, during the Eclipse of 

 August 7, 1869. C. A. Young. 



2. On the Relation between the Intensity of Light Produced from the 

 Combustion of Illuminating Gas and the Volume of Gas Consumed. Ben- 

 jamin Silliman. 



3. Notice of some New Tertiary and Cretaceous Fishes. O. C. Marsh. 



4. On the Distribution of the Native Tribes of Alaska and the Adjacent 

 Territory. W. H. Dall. 



The 'Troy, X. Y., Meeting, August, 1870. (Vol. ip) 



1. On Dispersion and the Possibility of Attaining Perfect Acromatism. 

 Edward C. Pickering. 



2. On the Former Existence of Local Glaciers in the White Mountains. 

 Louis Agassiz. 



3. On the Relations of the Order of Mammals. Theodore Gill. 



4. Investigations of the Development of Yeast or Zymatic Fungus. Theo- 

 dore Hilgard. 



