12 G PROCEEDINGS OF THE BOARD OF REGENTS. 



the constant play of tlie sea had worn it, but from what I saw I rather inferred 

 that the gradual approach had not been noticed, and I believe at some other 

 points there is unmistakable evidence. If these facts are of any use to science, 

 they ai-e at youi" disposal. 



[The facts presented in the above communication are very interesting, in con- 

 nection with similar observations at other points along our coast. They indicate 

 a movement in the strata of the earth. — J. H.l 



From Lmien Pratt, prqfessor of physics and cJiemistrt/, University of San Jose, 



Costa Rica. 



San Jos6 de Costa Rica, Fehruary 8, 1868. 



We have received through M. the minister of public instruction a magnificent 

 collection of the scientific memoirs of the Smithsonian Institution, which will 

 form the most precious part of the library of our university. I am authorized to 

 keep it in the laboratory, and I can assure you that, as far as we are concerned, 

 the object of the publication will be fully attained. It will essentially serve to 

 augment our stores of knowledge, especially in meteorology and geology. The 

 minister has, I believe, already written to the Smithsonian Institution in the name 

 of the Costa Rican government. Permit me, sir, specially to offer you my own 

 acknowledgments and to say how greatly I felicitate myself at seeing our labor- 

 atory placed in the relationship of exchange with one of the first scientific bodies 

 of the world. Regarding neither the paucity of the present population of the 

 country, nor the necessarily embryonic state of the University of San Jose, you 

 have looked only at our disposition to labor, to take part in the scientific move- 

 ment of the great nations, and you have treated us with a liberality for which I 

 know not how to express my gratitude. 



I was about to solicit an order to send you a collection of the ores of the 

 country and of the most characteristic rocks among those which I have thus far 

 been able to collect, when this very order was issued to me. I have, therefore, 

 prepared two small cases, enclosing 39 select specimens of the ores of gold and 

 silver of Costa Rica, as well as of some eruptive rocks and principal limestones 

 known in the country.* These two cases I propose to despatch by the mail of 

 day after to-morrow. 



The specimens of ores of gold and silver are accompanied only by a designation 

 of the locality ; by the next post I shall have the honor of addressing you a 

 copy of an official table drawn up by one of the judges of mines, in which you 

 will find all the indications relative to the value of the ores. I send no table of 

 analysis, because this analysis would apply only to isolated specimens or at most 

 to an av^erage of specimens, and would never have the practical signification of 

 the results obtained by the exploitation. Neither have I sent any specimen of 

 the enveloping stratum, because the specimens which I have at the university 

 have been taken rather too near the surface, and it is impossible to recognize in 

 the decomposed rock any mineralogical character Avhich would authorize a deter- 

 mination respecting the formation itself. It should be added that I have not yet 

 been able to proceed to a study of the conditions of the bearings on the spot. 

 As soon as I shall have found time to make a geological reconnaissance of the 

 principal Costa Rican mines, I will send you a statement of my observations, 

 and will submit to you at the same time specimens of the rocks in support of my 

 determinations. It would be very interesting to see whether the law of Hum- 

 boldt applies to Central America, and whether it be really necessary always to 



* These specimens have been received at the Institution. 



