4(j4 Siientijic Intelligence. [Junk, 



vi these mountains is unknown ; but as their summits are perpe- 

 tually covered with snow, we are sure that it at least exceeds 8000 

 feet. It runs in a northerly direction for nearly three degrees of 

 latitude ; then easterly, with still a northerly inclination, for six 

 degrees of latitude ; then nearly south ; afterwards south-east ; and 

 lastly, nearly east, over a space occupying nine degrees of latitude 

 and 13 degrees of longitude. Its size is fully as great above a 

 thousand miles before it joins the Mississippi as at the junction, yet 

 a great number of large rivers join it in the interval. Tliis shows 

 us the great evaporation to which it is subjected. It joins the 

 Mississippi nearly in north latitude 39°, west longitude 90°, from 

 Greenwich. The Mississippi, after this junction, flows for 10° of 

 latitude south, a course, including the windings, certainly not so 

 little as 2000 miles ; so that the whole course of the Missouri, from 

 its source to the ocean, exceeds 5000 miles. This is a length, of 

 course, that will not easily be paralleled any where else ; and 

 almost the whole of this immense river is navigable. What is still 

 more important, a great part ot" its banks consist of fertile plains ; 

 and from the observations of Lewis and Clarke, it would appear that 

 a coal country occupies about a thousand miles of these plains. 

 What a country is this likely one day to become 1 



II. An Analogy respecting Volcanoes. 



TI)e phenomena of volcanoes are some of tliose that liave hitherto 

 baflled the sagacity of philosophers. Hence I conceive that every 

 analogy which has any tendency to throw light upon their origin, 

 however insignificant in itself, ought not to be neglected. This 

 induces me to venture to state the following one. Some time ago 

 I got a salt from Mr. Trimmer, wiiich is sublimed during the burn- 

 ing of London bricks. Mr. Trimmer informed me that the sand 

 which is mixed with the clay in the bricks is brought from below 

 W'oolwich, and is therefore in all probability impregnated with 

 connnon salt. This will account for tli& acid in the sal-ammoniac. 

 I was at a loss to account for the decomposition of the common salt ; 

 but a correspondent from Bristol {Annals of P hilosophy , v. 157,) 

 suggests that sulphate of ammonia is generally formed during the 

 combustion of coal. This must no doubt be the case, as pyrites is 

 almost a constant companion of pit coal. Here, then, we have 

 during the burning of bricks containing common salt by common 

 pit (joil the sublimation of sal-ammoniac. Now it is well known 

 that sal-ammoniac is sublimed from Mount Vesuvius. Hence is it 

 not likely that the fuel which supports Vesuvius is coal, and that sea 

 water has access to it ? This supposition has been made long ago ; 

 but the preceding analogy seems to me to strengthen it. Would it 

 not be proper to ascertain whetlier sal-ammoniac be sublimed from 

 all volcanoes ? and if not, whether there be any thing peculiar in 

 the position and geology of those that yield this salt ? If all volca- 

 noes yield sal-ammoiilac, I should be inclined to suspect that the 

 quantity of coal contained iu the bowels of the earth is much 



