•z. 4G Gases, Acids, Salts, ^c. 



then tlie series commence. One series of these little cubes 

 will be deposited after another, the last lies on the preced- 

 ing, so that one half of each block lies upon the last, with 

 one half projecting. These successive series continue until 

 the hopper is formed. It may be called a hollow pyramid, 

 with steps inside and out. I have often seen them thus 

 formed artificially, from two to three inches in diameter. 

 After the hopper is formed, and generally before its sides are 

 built up to its final height, cubic blocks arc deposited in the 

 same order inside. And these hoppers within hoppers are 

 deposited until the solid cube is finished. 



After observing this process, go to Manlius Center, and 

 examine the ledge immediately adjoining the south bank of 

 the canal, fifty-tvi^o miles west of Utica. Here you may find 

 thousands of the empty moulds of these hoppers. We got 

 out several masses of the soft lias rock at this place, and cut 

 them across so as to open and show the outside and inside 

 impressions in perfection, which were four and five inches in 

 diameter. That the rock was deposited while in a soft state, 

 upon the solid crystals, and the salt was afterwards dissolv- 

 ed, leaving the space it occupied empty, seems not to admit 

 of a doubt. But what changes have taken place which 

 should produce solid crystals at one time, and dissolve them 

 at another? 



Numerous specimens may be found which present every 

 imitative form of the crystals in their progress from the hop- 

 per-form to the solid crystal. But at this locality, we find 

 more specimens which present the hollow, than the solid 

 crystal. The examination should commence here in prefer- 

 ence to any place we visited, because it aifords such large 

 and perfect specimens. 



Lastly, compare these pseudomorphous crystals of several 

 localities. They may be found every where in the bank of 

 the Salina branch of the canal, where it is cut through the 

 rock in the village of Salina. Also in the south rock bank 

 of the canal, one and a half miles west of the village of Jor- 

 dan, eighty-two miles west of Utica. We found none so 

 large at any place as at Manlius. Perhaps the characters of 

 the rocks may have an influence. At Manlius, as before 

 observed, the rock is lias ; but at the other localities it is the 

 red and grey saliferous rock of the marle-slate variety. 



In the first part of the canal reports, I mentioned, that 

 acicular crystals of common salt shot out from a specimen 



