A. Hall — Nova Andromeda,. 299 



a much more satisfactory expression of the shape of the uplift, 

 and to determine either that it is intimately related to the form 

 of the body of water removed, or that it is not so related. Tf 

 the relation were demonstrated, the observations might so far 

 indicate its nature as to render possible an evaluation of the 

 rigidity of the earth's crust. 



Another profitable method of continuing the inquiry would 

 be to make a similar investigation of the shore of another ex- 

 tinct lake, for example, the one to which Clarence King has 

 given the name of Lahontan, and which ranks second to Lake 

 Bonneville among the Quaternary lakes of the Great Basin. If 

 in a second instance the center of the desiccated lake were 

 found to be the locus of upheaval, the hydrostatic theory would 

 be practically established. 



It is hardly necessary for me to assure you that my personal 

 regret in abandoning this research at its present stage is very 

 great. I have discussed it as an investigation of the deforma- 

 tion of the Bonneville basin, but it has a broader meaning. 

 The condition of the interior of the- earth is one of the great 

 problems of our generation. Those who have approached it 

 from the geologic side have based a broad induction on the 

 structural phenomena of the visible portion of the earth's crust, 

 and have reached the conclusion that the nucleus is mobile. 

 Those who have approached it from the physical and astro- 

 nomic side have reached the conclusion that the nucleus is 

 rigid. Here seems an opportunity for a crucial observation. 

 If the crust of the earth floats upon a fluid nucleus, the evap- 

 oration of Lake Bonneville, by lifting from it a great weight, 

 must have produced an uplift of determinate form. If the 

 whole earth is solid, such a result could not have been wrought. 

 The decisive phenomena are known to exist, and to be accessi- 

 ble, but they are scattered over a broad desert, and they can 

 be gathered in only at the cost of much money and great 

 labor. 



Akt. XXVIII. — Nova Andromeda? ; by Asaph Hall. 



(Communicated by Geo. E. Belknap, Commodore U. S. N., Superintendent.) 



At the end of last August Dr. Hartwig, of Dorpat, an- 

 nounced the appearance of a new star in the great Nebula of 

 Andromeda. This announcement aroused much interest and 

 brought out a great deal of speculation on the origin of these 

 new stars, and on the nature of the nebulas and their connec- 

 tion with our sidereal system. Quite naturally in such a case, 



