Popular Science Monthly/Volume 14/December 1878/Correspondence
CURIOUS MOUNDS IN CALIFORNIA.
To the Editor of the Popular Science Monthly.
ON the stage-road from Mariposa to Merced—a portion of the Yosemite Valley route—for a distance of twenty miles, the surface of the ground, as far as the eye can see, is singularly characterized.
Circular elevations, like mammæ, about two feet high and twenty feet in diameter, are divided by shallow ditches, or swales, about ten feet wide. These mounds are surprisingly symmetrical, and occupy the whole surface. Where the rising ground meets the sky, the outline is regularly scalloped. The freshets have in some places cut through to the depth of three feet, leaving the vertical section exposed to view.
All the stones contained in the mounds are rounded, and in size are from half an inch to four inches in diameter. None larger were seen. The bottoms of the dry water-courses are paved with these round stones to a considerable depth, the largest on top. For six inches in depth of the surface of the mounds the soil is free of stones; below that, the stones are distributed without much regard to size, the spectator being impressed with the apparent fact that the larger ones are nearer the surface.
Rising ground equally with level surface is covered by these mammæ. In rare cases are two mounds thrown together, so as to interfere with the generally symmetrical arrangement. A plausible explanation of the cause of this phenomenon occurred to me: After the surface had been smoothed, and the large elevations rounded, by the moving glacier, the ice-mass became stationary from diminished thickness. The larger stones on the surface would melt through, forming funnel-shaped cavities, into which the water on the surface of the glacier would pour and run out at the bottom, leaving the accompanying dirt and gravel in a heap. But this theory requires that the stones causing the funnel-shaped cavities should be distributed on the surface of the glacier at uniform distances of twenty-five feet from each other, which supposition is inadmissible.
I am constrained to ask for a proper interpretation of the origin of this notable arrangement.
| S. H. Mead. |
| Davenport, Iowa, July 11, 1878. |
MUTILATIONS AND HEREDITY.
To the Editor of the Popular Science Monthly.
In January, 1875, I had a tortoise-shell cat that lost her left fore-paw, as I suppose, in a steel trap. About ten weeks after this accident she had a litter of kittens, and, one being a tortoise-shell, it was saved. The first cat lived about a year. In addition to her limping around on three feet, she had a peculiar habit of holding up the lame foot against her breast, as though she was nursing it, and would frequently come and touch me with it, looking up at me with a pitiful expression on her face. Last spring I obtained a tortoise-shell kitten, a granddaughter of the lame one and a daughter of the cat that was born after the foot was hurt. Now, this kitten has the habit of standing almost constantly on three feet, holding the left one from the ground (sometimes, but not often, she holds up the right one), and she frequently holds it to her breast, as though she were nursing it, in exact imitation of her grandmother, the lame one. She also has the habit of coming up and touching me with her paw, putting on the pitiful expression of countenance that was observed on the face of her ancestor.
| J. D. A. |
| Cromwell, Connecticut, October 21, 1878. |
DOES THE MICROPHONE MAGNIFY SOUND?
To the Editor of the Popular Science Monthly.
Sir: The account of the actual accomplishments of the microphone, in the way of magnifying faint sounds, as communicated to the Royal Society in May last, was so astonishing that every one was led to believe a scientific discovery of immense value had been given to the world, containing in embryo practical applications of unbounded extent.
Not the least remarkable feature of this discovery was the extreme simplicity of the apparatus, thereby enabling the merest dilettante to repeat the experiments detailed in Prof Hughes's paper; and I doubt not that a number of experimenters have expended a good deal of time and patience in endeavoring to develop these embryonic possibilities.
It is for the purpose of eliciting the candid opinion of such workers, who may have been more successful than I, that I am induced, through the medium of your valuable journal (while avoiding theoretical considerations which have been exhaustively discussed), to state very briefly the conclusions that I have arrived at after a careful investigation with microphones of varied form:
1. The microphone does not magnify sound, and we cannot expect it, "when further developed by study, to do for us, with regard to faint sounds, what the microscope does with matter too small for human vision."
We cannot correctly regard the sound heard in the telephone receiver as "a magnified image" of the original vibrations; for, while the fundamental tone is reproduced with considerable accuracy, the harmonics or overtones, giving the timbre, or individuality to the sound, are in most cases very imperfectly rendered.
2. If the ear is placed in as favorable a position to hear the original faint vibrations (which jar the delicately-poised piece of carbon) as it is when listening to the telephone, it will be found that the increased volume of sound issuing from the diaphragm of the receiver is more imaginary than real.
For these, and other reasons, the writer is of the opinion that the probable future value of this discovery has been greatly exaggerated, and that it is likely to prove an addition to the rather plentiful crop of scientific green fruit which fails to ripen into the full perfection so enthusiastically predicted by the luxuriance of the blossoms.
| Respectfully yours, |
| A. E. Outerbridge, Jr., |
| Assay Laboratory U.S. Mint, Philadelphia. |