HEART′BURN. Syn. Cardialgia, L. Anxiety and pain about the region of the stomach, generally attended by a sense of gnawing and heat; hence its popular name. Faintness, nausea, and eructation of a thin, acidulous, watery liquid, especially in the morning, are common symptoms of this complaint. The usual causes of heartburn are excess in eating and drinking, the use of improper food, and sedentary habits. A good remedy is a teaspoonful of carbonate of magnesia, or carbonate of soda, in a glass of peppermint or cinnamon water, to which a little powdered ginger may be added with advantage. This dose may be taken 2 or 3 times daily until the disease is removed. Articles of food that easily undergo fermentation should at the same time be avoided, and a dry diet had recourse to as much as possible. Soda water, toast-and-water, and weak spirit-and-water, are the most suitable beverages in this complaint.

HEAT. Syn. Caloric; Caloricum, L. The consideration of this subject belongs to physics and chemistry. Much useful information, in connection with it, will, however, be found in this work under the heads Ebullition, Evaporation, Expansion, Refrigeration, &c.

HEAVY SPAR. Native sulphate of barium. See Baryta.

HED′ERIN. Syn. Hederina, L. From the decoction of the ground seeds of ivy (Hedera helix), boiled in water, along with a little slaked lime or magnesia, the precipitate being afterwards digested in rectified spirit, and the filtered tincture evaporated. Febrifuge and sudorific.

HEIGHT, Average of Man. The ‘Boston Journal of Chemistry’ gives the following particulars of the average height of man:—“The Yankee would appear to be the tallest of civilised men, if we may trust some statistics given in foreign journals as the result of the measurement of over half a million men. The mean height of the American Indian is 67·934 inches; of the American white man, 67·672; Scotch, 67·066; English, 66·575; Russian, 66·393; French, 66·277; Mexican, 66·110.” If the Yankee carries off the palm as the tallest of men, he also does so for his tallest tales; but if weight were introduced into the calculation, we think our Transatlantic cousins would rank last.

HEIGHTS. The following table, calculated by Regnault, gives the temperature at which water boils at the corresponding heights of the barometric column. The figures have been confirmed by direct observation.

Boiling Points of Water at different Pressures.

Boiling Point. Deg. Fahr.Barometer. Inches.Boiling Point. Deg. Fahr.Barometer. Inches.Boiling Point. Deg. Fahr.Barometer. Inches.
18416·67619521·12420626·529
18517·04719621·57620727·068
18617·42119722·03020827·614
18717·80319822·49820928·183
18818·19619922·96521028·744
18918·59320023·45421129·331
19019·99220123·93721229·922
19119·40720224·44121330·516
19219·82220325·01421431·120
19320·25420425·46821531·730
19420·68720525·99221632·350

HEL′ENIN. See Inulin.

HELIOG′RAPHY. See Photography.