356 



tlie fisl], then press out the oil, and afterwards dry and grind the 

 remainder, mixing some gypsum, limestone, or earthy material, 

 in order to render the grinding more perfect. Sometimes they add 

 sulphuric acid to the fish-cake, and convert the bones of the fish 

 into superphosphate of lime, and the flesh into sulphate of ammo- 

 nia and humus, according to the method first indicated by Dr. 

 Hare of Philadelphia. In case this method is employed, the 

 acid fish-cake should be ground with limestone, when the excess 

 of sulphuric acid will form sulphate of lime, and render the 

 addition of gypsum unnecessary. 



It has been proposed to add a certain proportion of peat to the 

 fish-cake, during the operation of grinding it ; the peat acting as 

 an excellent absorbent of ammonia, and as an antiseptic. This 

 is applicable to the fish-cake that has not been treated with 

 sulphuric acid. 



Properly prepared fish-cake is fully equal to guano as a fer- 

 tilizer, and it can be prepared at a much lower cost than guano 

 can be brought from the coast of Peru. There are doubtless 

 many places on our coast where fish can be obtained in adequate 

 quantities for the manufacture of this manure. 



Dr. Charles Pickering gave an account of the late 

 volcanic eruptions upon the island of Hawaii, explain- 

 ing, by means of diagranns, the positions of Mauna Loa 

 and Mauna Kea, and the course of the lava stream to- 

 wards the coast. 



Dr. Jackson observed that the Hawaiian lava was one 

 of the most fusible of known lavas, and he instanced the 

 so-called Pele's hair, which is very fusible in the flame of 

 a common candle. 



Dr. Pickering stated that Pele's hair was a kind of 

 glass, the product of the volcanic eruption under peculiar 

 circumstances. The true lava was no more fusible than 

 that from other localities. 



A letter was read from Oliver H. Holden, Esq., of 

 Melbourne, Australia, accompanying a valuable donation 

 from the Government Museum of Natural History, at 



