462 Etymology.

463 Dictionaries.

464 Synonyms.

465 Grammar.

466 Prosody.

467 Dialects.

468 Texts.

469 Portuguese.

=470 Latin.= 471 Orthography.

472 Etymology.

473 Dictionaries.

474 Synonyms.

475 Grammar.

476 Prosody.

477 Dialects.

478 Texts.

479 Medieval Latin.

=480 Greek.= 481 Orthography.

482 Etymology.

483 Dictionaries.

484 Synonyms.

485 Grammar.

486 Prosody.

487 Dialects.

488 Texts.

489 Modern Greek.

=490 Other Languages.= 491 Chinese.

492 Egyptian.

493 Semitic.

494 Indian.

495 Iranian.

496 Keltic.

497 Slavic.

498 Scandinavian.

499 Other.

NATURAL SCIENCE.

=500 Natural Science.= 501 Philosophy.

502 Compends.

503 Dictionaries.

504 Essays.

505 Periodicals.

506 Societies.

507 Education.

508 Travels.

509 History.

=5l0 Mathematics.= 511 Arithmetic.

512 Algebra.

513 Geometry.

514 Trigonometry.

515 Conic sections.

516 a.n.a.lytical geometry.

517 Calculus.

518 Quaternions.

519 Probabilities.

=520 Astronomy.= 521 Theoretical.

522 Practical.

523 Descriptive.

524 Maps.

525 Observations.

526 Figure of the earth.

527 Navigation.

528 Almanacs.

529 Chronology.

=530 Physics.= 531 Mechanics.

532 Hydrostatics.

533 Pneumatics.

534 Acoustics.

535 Optics.

536 Heat.

537 Electricity.

538 Magnetism.

539 Molecular physics.

=540 Chemistry.= 541 Theoretical.

542 Experimental.

543 a.n.a.lysis.

544 _Qualitative._ 545 _Quant.i.tative._ 546 Inorganic.

547 Organic.

548 Crystallography.

549 Mineralogy.

=550 Geology.= 551 Physical Geography, Meteorology.

552 Lithology.

553 Dynamical geology.

554 Europe.

555 Asia.

556 Africa.

557 North America.