Mr. Jefferson (Ex-President United States) sends a note of thanks (Jan. 26th) in the following words:  “It is a valuable element towards the knowledge we wish to obtain of the crust of the globe we inhabit; and, as crust alone is immediately interesting to us, we are only to guard against drawing our conclusions deeper than we dig.  You are entitled to the thanks of the lovers of science for the preservation of this fact.”

Mr. John Adams (Ex-President United States, Jan. 27th) says:  “I thank you for your memoir on the fossil tree, which is very well written; and the conjectures on the processes of nature in producing it are plausible and probable.

“I once lay a week wind-bound in Portland road, in England, and went often ashore, and ascended the mountain from whence they get all the Portland stone that they employ in building.  In a morning walk with some of the American passengers from the Lucretia, Captain Calehan, we passed by a handsome house, at the foot of the hill, with a handsome front yard before it.  Upon the top of one of the posts of this yard lay a fish, coiled up in a spiral figure, which caught my eye.  I stopped and gazed at it with some curiosity.  Presently a person, in the habit and appearance of a substantial and well-bred English gentleman, appeared at his door and addressed me.  ’Sir, I perceive that your attention is fixed on my fish.  That is a conger eel—­a species that abounds in these seas; we see them repeatedly, at the depth of twelve feet water, lying exactly in that position.  That stone, as it now appears, was dug up from the bowels of this mountain, at the depth of twenty feet below the surface, in the midst of the rocks.  Now, sir,’ said he, ’at the time of the deluge, these neighboring seas were thrown up into that mountain, and this fish, lying at the bottom, was thrown up with the rest, and then petrified, in the very posture in which he lay.’

“I was charmed with the eloquence of this profound philosopher, as well as with his civility, and said that I could not account for the phenomenon by any more plausible or probable hypothesis.

“This is a lofty hill and very steep, and in the road up and down, there are flat and smooth rocks of considerable extent.  The commerce in Portland stone frequently calls for huge masses, from ten to fifteen tons weight.  These are loaded on very strong wheels, and drawn by ten or twelve pair of horses.  When they come to one of those flat rocks on the side of the hill where the descent is steep, they take off six or eight pair of horses, and attach them behind the wagon, and lash them up hill, while one or two pair of horses in front have to drag the wagon and its load and six or eight pair of horses behind it, backwards.

“I give you this history by way of comment on Dr. Franklin’s famous argument against a mixed government.  That great man ought not to have quoted this as a New England custom, because it was an English practice before New England existed, and is a happy illustration of the necessity of a balanced government.