Page:Popular Science Monthly Volume 24.djvu/571

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CORRESPONDENCE.

sible!" said he, and proposed, as the tree had been felled and lay on the ground, to go over and count the rings, to which I assented, and looked on while the professor undertook the task. I soon saw that he was under considerable perplexity. He said he found it no easy matter, as some of the rings were so indistinct that he was unable to decide whether they were single or double, "but," said he, "I can make out thirty or more, but how many more I will not venture to say." I carefully examined the rings, and saw what I had seen before. I have no doubt that at least forty rings could have been identified by a close and critical examination. I reiterated my statement as to the real age of the tree, for thirty years before I had seen corn growing on this spot.

I told him the tree which he had just examined presented a true record of the weather, so far as drought and rainfall were concerned, since it had been a tree, and invited him to call at my office and examine the records which I had kept during the same period, and he would find a confirmation of what I had stated. "This theory," says he, "is new to me, but it is plausible, and the facts here presented seem to substantiate it." His death, after his return North that year, put a stop to further scientific investigations in Florida on his part, but the reasons then given have induced many others to change their views as to the value of concentric rings in determining the age of trees. In a climate like that of Florida they certainly are not to be depended on; how it may be in a more northern latitude I will not undertake to assert or deny, but it seems to me probable that any arrest of growth, from climatic or other causes, will be indicated by some peculiarity in the formation of the concentric rings of the tree; and it may in some instances present two rings instead of one to mark an entire year's growth.

Very respectfully,
A. S. Baldwin, M. D.
Jacksonville, Fla., September 27, 1883.
 

 

BIRTH-RATE IN A NEW HAMPSHIRE TOWN.

Messrs. Editors:

While preparing a history of Chesterfield, Cheshire County, New Hampshire, the writer has had occasion to collect the birthrecords of several hundred families, including both original settlers and their descendants. These families may be regarded as typical New England families, the original settlers having come, for the most part, from Massachusetts, Connecticut, and Rhode Island. The foreign element has always been very small in the town. A careful inspection of the birth-records in question (taking into account the children of one marriage only, in cases in which the father married more than once, and excluding the still-born) yields the following results:

1. The total number of births in 165 families, from 1750 to 1810, was 1,359, or an average number of 8 13/55 to each family.

2. The total number of births in 328 families, from 1810 to 1870, was 1,825, or an average number of 5 185/328to each family.

3. The average number of births in 140 families, from 1810 to 1840, was 6 42/70.

These figures show that there was a marked decrease in the birth-rate of Chesterfield families between 1810 and 1840, and that in the period of sixty years, from 1810 to 1870, this decrease was still more marked.

If what is true of this town, in this respect, is also true of the majority of New England towns, as is quite probable, it would appear that the birth-rate in New England families has steadily decreased since the introduction of railroads and the extensive establishment of manufactories.

O. E. Randall.
West Chesterfield, N. H., September 3, 1833.
 

 

"TIDAL ANOMALIES."

Messrs. Editors:

In the January number of your journal there is a communication under the above-Named title, from G. W. Grim, of the bark Coryphene. Referring to a preceding letter of mine, he says of my article, "After demonstrating, as a result of Professor Schneider's theory, a great inequality in the daily range of the tides," etc.

The gentleman entirely misconceives the purport of my criticism. I showed that Professor Schneider's theory is demonstrably false, and my reference to the New York tides was merely to show by them that the theory does not conform to the facts. The "daily inequality" is easy to explain: most of those given by Mr. Grim present no difficulty at all—with others, when the facts are established, the explanation will follow.

No theory of the tides is of any value except as based on facts—in which respect Mr. Grim's theory is worse off than Mr. Schneider's. A theory of the tides resting solely on one's inner consciousness is not a valuable contribution to knowledge.

R. W. McFarland.
Ohio State University, December 27, 1883.
 

 

CARRYING-POWER OF FLUID CURRENTS.

Messrs. Editors:

I see that in your November number, page 95, Mr. Carter applies the "law of carrying-power of currents" (R ɑ v6) to blood-currents carrying waste matter. Now, I make no objection to the general correctness of Mr. Carter's conclusions, but I am