# Popular Science Monthly/Volume 14/February 1879/Correspondence

CORRESPONDENCE.

To the Editors of the Popular Science Monthly.

GENTLEMEN: In your December number, under the heading "Editor's Table," you Socratically repeat the statement that Dr. Lardner declared that steam-navigation across the Atlantic was impracticable. This statement you will find on examination to be incorrect; and, as I consider that your publication is well adapted to make known the facts in the case, I transmit them to you, in the hope that you will publish them, and so contribute to their becoming generally known. Scientific men, as necessarily lovers of truth and exactness, can not but desire that such a statement should not be continued unless founded on the basis to which it pretends. General readers will soon adopt the correction of the error if properly laid before them, notwithstanding a possible bias toward enjoying what they at present regard as a disproved fallacy advanced by a very able man. The facts are as follows:

In 1828 there was published in New York, by Elam Bliss, 128 Broadway, an edition of Dr. Lardner's "Popular Lectures on the Steam-Engine, . . . with additions by James Renwick, Professor of Natural Experimental Philosophy and Chemistry in Columbia College, New York." Mr. Renwick in his preface says: "A few additions have been considered necessary. . . . They may be distinguished from the original paragraphs of the text from their being marked by letters instead of numbers, and their having the initials A. E. subscribed to each of them."

At page 157 of the work I refer to, the eleventh lecture of Dr. Lardner will be found to commence with this proposition: "One of the most interesting and important uses of the steam-engine is its application to nautical purposes. There are various ways in which this machine may be used in propelling a vessel through the deep; but that which is now universally adopted is by giving, through its means, rotation to paddle-wheels placed at the side of the vessel." And Dr. Lardner further on says: "In 1812 steam-vessels were first introduced upon the Clyde, and since that period steam-navigation has rapidly extended, so that at present there is scarcely a part of the civilized globe to which it has not found its way. The Atlantic and Pacific Oceans have been traversed by its powers, and if the prolific results of human invention should suggest means of diminishing the consumption of fuel, or obtaining a supply of heat from materials sufficiently small and light, it would be hard to assign limits to the powers of this most wonderful agent.

Now, we have here from Dr. Lardner the broadest statement possible from so careful and exact a man, that he rather expected "the prolific results of human invention," not only to render "steam-navigation across the Atlantic" practicable, but to carry the uses of steam so far that he would not venture to assign limits to them. And the whole of his eleventh lecture is in this sense and tone.

But Mr. Renwick, at page 167 of the quoted work, has this note:

"(k.) The steam-engine may compete successfully with the wind as a propeller of vessels, whenever certainty of conveyance becomes important, as in the case of passage-boats upon lakes and rivers. But there are cases where steam becomes inapplicable to navigation. Upon the open ocean, although the safety of steamships has been fully tested, the vast quantity of fuel necessary in a long passage will prevent its use in distant voyages, and it is besides far less economic than the propulsion by means of sails. (A. E.)"

I have italicized a few of the more important words in these extracts, which show that it was not Dr. Lardner but Mr. Renwick who has to take the responsibility of having said that "steam-navigation across the Atlantic was impracticable."

Respectfully,

 James Burns, M. D.⁠ ⁠New Orleans, December 7, 1878.

INSECTS AND COLORED FLOWERS.

To the Editors of the Popular Science Monthly.

During the summer I have spent much of my time in a porch surrounded by petunias and morning-glories, of all shades of color from white to bright purple and dark violet. I first observed that the colored petunias were torn to pieces every day before noon, while the white or pale ones escaped almost uninjured. I soon discovered that the bees and butterflies were the mischief-makers, and that the damage was done with their sharp claws in struggling to get to the bottom of the flower-cup. I kept a close watch down to the present day—when the bees and butterflies are gone, and a few blossoms still remain, never molested—and my first impressions have been fully confirmed. In every variety of situation and circumstances the white petunias have been neglected for the colored, in exact proportion to the intensity and vividness of color; and the same I found to be true, in a less degree, as regards the deep and pale morning-glories. I have called the attention of others to the facts, and proved that the preference of the insects is determined by color alone. If there was any difference whatever in sweetness or fragrance, it was in favor of the rejected white flowers.

Yours respectfully,

 Thomas D. Lilly.⁠ Kent's Store, Fluvanna County, Va. ${\displaystyle {\begin{matrix}{\big \}}\end{matrix}}}$ October 23, 1878.⁠

AN AMERICAN HAIRY TORTOISE.

To the Editors of the Popular Science Monthly.

Noticing your interesting extract, from "Land and Water," concerning the hairy tortoise, I take the liberty of mentioning a similar species found, to my knowledge, in the lakes of this valley. Its description tallies almost exactly with that of the Chinese variety, except perhaps in size. It is about three inches in length by two and a half in breadth, is very closely covered by its shell; the calipee is not hinged, and out of some dozen specimens examined by me not one was without the coat of water-grass. Its habitat is the bottom of shallow lakes and ponds, and near the submerged roots of trees, where it is often caught with the hook. It has a remarkably fetid odor. The grassy or confervoid covering is not of any very great length, generally about one half or three fourths of an inch. It is, I believe, an undescribed species, though Mr. Agassiz may have had a specimen among his collection of tortoises from the Mississippi Valley.

Very respectfully,

 J. F. Battaile.⁠ ⁠Yazoo City, Mississippi, December 8, 1878.