A perusal of the communications contained in this paper lead to the impression that their writer accepts many of the theories advanced by Brasseur de Bourbourg, that he is a believer in the interpretations of Landa, and that he thinks he has been able to establish a system which enables him to read Maya inscriptions. Dr. Le Plongeon has been accompanied and assisted in all his labors by his accomplished wife, and he has frequently stated that a great part of the credit for the results achieved is due to her intelligent judgment and skilful execution. His last date is from Belize, British Honduras, September 1. In that letter he announces the preparation of a paper for the Royal Geographical Society of London, in which he says he shall give his researches _in extenso_. After four years of toil and exposure to danger, and after a large expenditure of money paid for services in opening roads, clearing ruins, and making excavations, Dr. Le Plongeon finds himself deprived of all the material results of his labors and sacrifices which could secure him an adequate return. We hope that he may soon receive just and satisfactory treatment from the government, and a fitting recognition and remuneration from the scientific world. In judging of the subject here presented, the reader will bear in mind that facts substantiated should not be rejected, even if the theories founded on them advance beyond the light of present information. * * * * * In August, Dr. Le Plongeon sent the following letter with the request that it should be published in a form which would allow of its presentation to the _Congrès International des Américanistes_, which would be held at Luxembourg in the month of September. It was printed in the Boston Daily Advertiser, in the issues of Sept. 3d and 4th, and is now repeated in the same type in this connection. The spelling of the name Chac-Mool in the letter was changed by the writer from that employed in the text by Dr. Le Plongeon, which is invariably _Chaacmol_; a liberty taken in consequence of the unanimous preference in favor of the spelling Chac-Mool shown in all the written or printed articles from Yucatan relating to this discovery, which have come to our observation. Copies of the letter were sent to Luxembourg, and also to the Bureau of the Société des Américanistes at Paris. LETTER FROM DR. LE PLONGEON. ISLAND OF COZUMEL, YUCATAN,} June 15, 1877. } _Stephen Salisbury, jr., esq., Worcester, Mass.:_--