2IO 



THE MUSEUM. 



the ever revolving pitch." The true 

 cause of the revolving motion of the 

 pitch, and of the structure resulting 

 therefrom, is apparently the great diur- 

 nal range in the temperature of the 

 surface of the lake. On unclouded 

 days the asphalt attains a temperature 

 of about 140 degrees P., and sinks 

 during the night to 70 or 60 degrees 

 suffering a variation of 70 to 80 degrees 

 which must produce a considerable 

 change of the volume. This expan- 

 sion is superficial, and its chief ten- 

 dency is to extend the pitch horizon- 

 tally. Where the pitch is covered by 

 water, it will not experience this alter- 

 ation of volume; and these protected 

 areas are forced downward by the ex- 

 pansion of the unprotected areas. 



No soundings have ever been made 

 in this lake, and its depth is unknown. 

 The thickness of the deposit is, of 

 course, a factor of the first importance 

 in determining whether the suppply of 

 asphalt is likely to prove practically in- 

 exhaustible. In considering the ques- 

 tion of the probable permanence of the 

 supply, it is also important to remem- 

 ber that the material is doubtless es- 

 caping from the underlying asphaltic 

 sandstone, though perhaps very slowly. 



As regards its origin, the lake is be- 

 lieved not to differ essentially from any 

 of the patches of pitch scattered over 

 the surrounding county. It appears 

 to be simply a large puddle of pitch, 

 which has oozed out of the sandstone 

 and collected in a basin-like depression 

 in that rock. The observations of Mr. 

 Wall have placed the vegetable origin 

 of this bitumen beyond question. The 

 asphaltic sandrock is rich in vegetable 

 remains; and it is possible to trace 

 every step in the conversation of these 



into asphaltum, until the organic struct- 

 ure of the wood is entirely obliterated. 

 W. O. Crosby, in Swiss Cross. 



Fish Commission's Exhibit at At- 

 lanta- 



Among other attractive features of 

 the exhibit of the United States Fish 

 Commission at the Cotton States and 

 International Exposition, the scientific 

 investigations of the Commission will 

 be illustrated by casts of fish and other 

 animals from life, and by collections 

 of sponges, oysters, and other shell 

 fish, crabs, lobsters and shrimps, cor- 

 al, sea lillies, sea pens and numerous 

 other materials brought up in "the 

 dredging and trawling apparatus by 

 the vessels of the Commission. The 

 apparatus used in the collection of 

 these objects will also be shown, as 

 well as the complicated instruments 

 accessory to the work of deep sea and 

 inland investigation. In the division 

 of methods and statistics of the fisher- 

 ies, the relation of the Commission to 

 the fisheries will be shown by means 

 of types of vessels and other equip- 

 ments employed, and by charts and 

 tables showing the extent of the indus- 

 try in the United States. The Com- 

 mission has a great wealth of hand- 

 some pictures intended to beautify and 

 round out its exhibit, and of these as 

 many as the space will accommodate 

 will be shown at Atlanta. — Fis/iiiig- 

 Gazette. 



(iaiucsvillc, Florida, Jau. 7, '1)5 

 Mr. Walter F. Webb, Albiou, N. Y. 



My Dear Sir:— Your letter aud pamphlets 

 received today. I think it can be safely said 

 that the Mi seuini has no e(iual. The cuts are 

 beautiful and the reading is excellent. It is 

 worth a great deal more than the price of 

 subscrii)tion. I am dear sir, 



Sincerely yours. 

 Fkedekiok Davis. 



