CORRESP ONBENCE. 



555 



siblc ! " said he, and proposed, as the tree 

 had been foiled and lay on the ground, to 

 go over and count the rings, to which I as- 

 sented, 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 un- 

 able 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 

 conocrned, since it had been a tree, and in- 

 vited him to call at my office and examine 

 the records which I had kept during the 

 same period, and he would find a confirma- 

 tion of what I had stated. " This theory," 

 says he, " is new to me, but it is plausible, 

 and the facts here presented seem to sub- 

 stantiate it." His death, after his return 

 North that year, put a stop to further sci- 

 entific 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 de- 

 pended on ; how it may be in a more north- 

 ern latitude I will notMmdertake 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 tlie concentric rings of 

 the tree; and it may in some instances pre- 

 sent two rings instead of one to mark an 

 entire year's growth. 



Very respectfully, 



A. S. Baldwin, M. D. 

 Jaokboxville, Fla., September 27, 1SS8. 



BIRTH-KATE IN A NEW HAMPSHIRE 

 TOWN. 

 Metgr*. Editors: 



While preparing a history of Chester- 

 field. Cheshire County, New Hampshire, the 

 writer has had occasion to collect the birth- 

 records of several hundred families, includ- 

 ing both original settlers and their descend- 

 ants. These families may be regarded as 

 typical New England families, the original 

 settlers having come, for the roost part, 

 from Massachusetts, Connecticut, and Rhode 

 Island. The foreign element has always 

 been very small in the town. A careful in- 

 spection 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 1760 to 1810, was 1,359, or 

 an average number of 8^? to each family. 



2. The total number of births in 328 

 families, from 1810 to 1870, was 1,825, or 

 an average number of Sj^f J^ to each family. 



3. The average number of births in 140 

 families, from 1810 to 1840, was 6)3. 



These figures show that there was a 

 marked decrease in the birth-rate of Ches- 

 terfield 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 re- 

 spect, 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. 

 0. E. Randall. 



West Chesteehkld, N. H., September 8, 1S80. 



"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 dem- 

 onstrating, as a result of Professor Schnei- 

 der'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 demonstra- 

 bly 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 ea.sy to explain : 

 most of those given by Mr. Grim present no 

 difficulty at all — with others, when the fads 

 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. McFahland. 

 Ohio Statb U.mvbesitt, December 2T, 1883. 



CARRTINO-POWER OF FLUID CURRENTS. 



SfesKTS. Editors: 



I SEE that in your November number, 

 page 95, Mr. Carter applies the "law of 

 carrying-power of currents" (R a v*) to 

 blood-currents carrying waste matter. Now, 

 I make no objection to the general correct- 

 ness of Mr. Carter's conclusions, but I am 



