HALO 



2672 



HAM 



example of illusion is the feeling of motion ex- 

 perienced by one sitting in a train which is not 

 moving, when another train passes on a neigh- 

 boring track. 



Hallucinations, being effects rather than 

 causes, cannot medically be treated. Physicians 

 seek the basis of the disorder and, if that can 

 be cured, hallucinations cease. 



HA'LO, a word derived from the Greek 

 name for a threshing floor on which oxen, going 

 round and round, trod a circular path. It is 

 now applied in astronomy to luminous rings 

 round the sun and moon. Three of these cir- 

 cles of light are sometimes seen surrounding 

 the sun. Halos are probably formed by the re- 

 fraction of light from particles of ice and are 

 most common in Arctic regions. In addition to 

 the circle, a cross is sometimes seen, stretching 

 beyond the limits of the halo, and on the bands 

 of the cross occur parhelia or mock suns (see 

 PARHELION). The band round the sun and 

 moon is generally colored red on the inside, 

 tapering off into orange, yellow and white at 

 the edges. Coronas, sometimes called halos, 

 are not really such, and are due to different 

 causes (see CORONA). 



The halo is much used in art, and since the 

 fifth century few pictures of Christ or of a 

 saint have been painted without a luminous 

 circle nearly surrounding the head. It is re- 

 garded as an emblem of divinity and of purity 

 or saintliness. 



HALOGENS, hal'ogenz,. a name given to a 

 group of four chemical elements which resemble 

 each other in a general way as regards their 

 physical and chemical properties and which 

 form chemical compounds that also possess sim- 

 ilar properties. These four elements are bro- 

 mine, chlorine, fluorine and iodine, each of 

 which is treated under its own title in these 

 volumes. The name halogen is derived from 

 the Greek words hols, which means salt, and 

 genis, which means to produce, and signifies a 

 sea-salt producer. These elements have been 

 named halogens because they form salts which 

 resemble common or sea salt, which is a com- 

 pound of chlorine with sodium. See CHEMISTRY. 



HALS, hahlz, FRANS (about 1584-1666), an 

 artist who is regarded as the founder of the 

 Dutch school of genre painting. As a portrayer 

 of faces wreathed in laughter he has never been 

 equaled, and his subjects of feasting exhibit 

 great vivacity and spirit. His work is dedicated 

 to themes suggestive of peaceful enjoyment and 

 absolute placidity of purpose. Very little is 

 known of Hals himself. He was born at Ant- 



werp, and in his early manhood studied under 

 eminent instructors at Haarlem: He is espe- 

 cially famous as a portrait painter; eight nota- 

 ble examples are preserved in the museum of 

 Haarlem, the finest representing the officers of 

 the corps of Saint Adrian. His Mandoline 

 Player, now in the gallery of Amsterdam, is a 

 typical example of his treatment of single fig- 

 ures. As a teacher, Hals exercised a marked in- 

 fluence upon the development of Dutch art. 

 Several of his sons were artists, the most re- 

 nowned being FRANS HALS, the younger, who 

 lived about 1637 to 1669. 



HAM, a meat obtained from the thigh of 

 the hog, prepared for the consumer by the 

 processes of salting and smoking. Ham is fre- 

 quently known as lean pork, as distinguished 

 from bacon, which is fat pork. The amount of 



FOOD VALUE OF HAM 



It has a heating value of 1,875 calories per 

 pound, more than many other meats, and is there- 

 fore not in demand in warm weather. 



fat in prepared ham varies, the average for me- 

 dium-fat smoked hain being 33.4 per cent. The 

 fuel value for the same product is 1,875 calories 

 per pound (see CALORIE), as compared with 900 

 for medium-fat leg of mutton, and 840 for 

 smoked beef. Ham is nutritious, but less di- 

 gestible than bacon. It has an agreeable taste 

 and flavor and is served in a variety of ways, 

 fried ham being a staple breakfast meat, and 

 cold boiled ham being equally popular for sand- 

 wiches and as a luncheon meat. 



The curing of ham is an important branch of 

 the meat-packing industry, and it is also a 

 common farm industry. There are two methods 

 of salting, the wet-salting, or pickling, method, 

 and the dry-salting method. By the former the 

 hams are kept in brine from a month to a 

 month and a half, with occasional renewals of 

 the pickling liquid. The dry-salting method 

 consists in rubbing the meat thoroughly with 

 salt, and repeating the process at the end of ten 

 days and again at the end of another ten days. 

 After the salting the hams are hung in smoke- 



