HELVELLYN, one of the Cumberland mountains, 3118 ft. high, rises at the side of Ulleswater, midway between Keswick and Ambleside.

HELVETII, a Celtic people mentioned by Caesar as occupying territory in Central Europe now embraced in Switzerland; they suffered tremendous slaughter at the hands of Caesar when endeavouring to make their way to a wider territory in Southern Gaul.

HELVETIUS, a French philosophe, born in Paris, of Swiss origin; author of a book entitled “De l’Esprit,” which was condemned by the Parlement of Paris for views advocated in it that were considered derogatory to the dignity of man, and which exposed him to much bitter hostility, especially at the hands of the priests; man he reduced to a mere animal, made self-love the only motive of his actions, and the satisfaction of our sensuous desires the principle of morals, notwithstanding which he was a man of estimable character and of kindly disposition (1715-1771).

HEMANS, FELICIA DOROTHEA, nee Browne, poetess, born in Liverpool; her marriage was an unhappy one, and after the birth of five children ended in permanent separation; she was the authoress of a number of works, a complete edition of which occupies 7 vols., the best of her productions being lyrics; and she enjoyed the friendship of Wordsworth, Scott, and other literary celebrities of the time (1791-1835).

HENAULT, French historian, born in Paris, president of the Parlement of Paris; was author of “Abrege Chronologique de l’Histoire de France” (1685-1770).

HEMEL HEMPSTEAD (10), a busy market-town in Herts, 23 m.  NW. of London; noted for its straw-plaiting, and has paper-mills, foundries, &c.

HEMS or HOMS (35), a noted Syrian city known to the Romans as Emesa, on the Orontes, 63 m.  NE. of Tripoli; here stood in ancient times a famous temple of the Sun, one of whose priests, HELIOGABALUS (q. v.), became Roman emperor (218); the Crusaders captured it from the Saracens in 1098; it does a good trade in oil, cotton, silk, &c.

HEMSTERHUIS, Dutch philologist, born at Groeningen; was professor of Greek at Leyden; one of the greatest Grecians of his day; had for pupils Ruhnken and Valckenaer, and edited a number of classical works (1685-1766).

HENDERSON, ALEXANDER, a celebrated Scotch divine; became professor of Rhetoric and Philosophy in St. Andrews, and subsequently held the living of Leuchars, in Fife; he actively espoused the cause of the Covenanters, and became a prominent leader in negotiations with the king; in 1643 he drafted the “Solemn League and Covenant” which passed into force, and he was one of Scotland’s representatives to the Assembly of Divines at Westminster (1583-1646).

HENDERSON, THOMAS, astronomer, born at Dundee, astronomer first at the Cape and then Astronomer-royal for Scotland, calculated the distance of the nearest fixed star [Greek:  alpha] Centauri and found it nearly 19 billions of miles from the sun.