HEARTS 



39OO 



HEAT 



Card game somewhat 

 resembling whist (q.v.), except 

 that there are no partners. In 

 effect, it is a combination of ordin- 

 ary whist and the mi-sere call at 

 solo. The object of the game is to 

 get rid of every card of the heart 

 suit that a player may hold. Thus, 

 tricks may be taken if the round 

 contains no hearts, but should 

 hearts be contained in it, the 

 player endeavours to force the 

 trick upon one of his adversaries. 

 When a heart can be discarded this 

 should be done. The player hav- 

 ing the fewest or no hearts 

 receives from the others according 

 to the number of hearts they 

 may hold. 



Heart's Content. Port of New- 

 foundland. It stands on the E. 

 side of Trinity Bay, and has a good 

 ~*^mam h ar bour, used by 

 fishermen and others. 

 W *' Here is the termi- 

 I nus of the cables 

 y from Valentia, Ire- 

 1 land. Pop. 1,000. 



Heartsease( Viola 

 tricolor). Herb of the 

 natural order Viola- 

 ceae, native of Bri- 

 tain, N. Europe, N. 

 Africa, and Asia. It 

 differs conspicuously 

 from the violets in 

 the lyrate form of 

 leaf with leafy sti- 

 pules, and in the 

 sepals having ear- 

 like processes. The 

 small flowers are whitish, yellow and 



purple, the tints sometimes com- 

 bined in one flower, sometimes dis- 

 tinct. Among other popular names 

 for the flower were Love-in-idle- 

 ness, Three-faces-under-one-hood, 

 Pawnee or Pansy (Fr. pensee). 

 The latter name has been adopted 

 generally for the wonderful garden 

 forms that have been evolved by 

 selection from the little wild- 

 flower. See Pansy. 



Heartsee^Cardiospermum Mli- 

 cacabum). Climbing herb of the 

 natural order Rapindaceae. A 



Heartsease, 



flower and 



foliage 



Heartseed. Spray of ioliage with 

 flowers and seed pods 



native of the tropics, its leaves are 

 divided into coarsely toothed, 

 lance-shaped leaflets. The small 

 greenish-white flowers form short 

 sprays. The seed vessel is a blad- 

 der-like capsule, and the round 

 seeds bear a heart-shaped scar, 

 whence the name. An alternative 

 name is balloon vine. 



HEAT: THEORY AND MEASUREMENT 



J. Bice, M.A., Senior Lecturer in thysics, Liverpool 



Here are described the various theories of heat and its measurement, 

 serving as a general introduction to the many articles in this Ency- 

 clopedia dealing with heat in its various manifestations, and the 

 investigators in the subject. Such articles are Conduction ; Freezing 

 point ; Fusion ; Melting point ; Thermo- dynamics ; Thermometer ; 

 Dewar ; Joule; RegnauU 



The common sensations ex- 

 perienced by everyone who touches 

 the surface of a body leads to a 

 rough classification of bodies as 

 " hot " or " cold." Also the sensa- 

 tions experienced when in full view 

 of the sun or a fire, or even when 

 sufficiently close to a hot but non- 

 luminous body, and the observa- 

 tions of the tendency of bodies 

 which originally were unequally 

 hot to come to the same state of 

 hotness or coldness, impress on 

 our minds the idea of the trans- 

 ference of something which we 

 call " heat " from body to body. 

 A little trouble is required to avoid " 

 confusing our sensations of hotness 

 and the concept of " temperature " 

 based on them, with the concept of 

 heat. After all, temperature is the 

 name which we give to any conveni- 



ent measure which we make of a 

 body's condition as regards hotness, 

 while it is clear that the amounts of 

 heat involved in changing a body's 

 condition from one temperature to 

 another will not be determined 

 solely by those temperatures, but 

 will depend also on the mass of the 

 body and the nature of its material. 

 Historically the study of the 

 science of heat began with inves- 

 tigations concerning the measure- 

 ment of temperature. The sense 

 of touch is neither sufficiently sen- 

 sitive nor precise to serve as a 

 reliable guide in such matters. The 

 invention of the first thermometers 

 has been ascribed to various peo- 

 ple, but certainly Galileo's claim 

 is one of the best established, and 

 in the hands of his pupils who 

 formed the famous " Accademia 



del Cimento " at Florence, mea- 

 surement of temperature attained 

 a very fair standard of accuracy. 

 These Florentine academicians 

 adopted the glass bulb and stem, 

 containing either mercury or spirits 

 of wine, choosing as " fixed 

 points " the temperature of snow 

 in the severest frost and the tem- 

 perature of the bodies of cows 

 and deer, and divided the stem 

 between into 40 or 80 equal parts. 



G. H. Fahrenheit (1686-1736) 

 perfected the mercury in the glass 

 thermometer by discovering a 

 simple process for cleaning mer- 

 cury, and by observing that the 

 temperature of a boiling liquid 

 depends on the pressure impressed 

 on its surface by the atmosphere 

 or artificial means. Having taken 

 his zero to be marked when the 

 bulb was in a mixture of ice, sal- 

 ammoniac and water, and another 

 fixed point to be indicated when 

 the bulb was under the armpit of a 

 healthy person, he divided this 

 interval into 24 equal divisions ; 

 finding these to be too large, he sub- 

 di vided them into four equal parts. 

 F. and C. Thermometers 



On this scale he found that 

 pure melting ice gave constantly 

 32, and he no doubt used this 

 as a check on his graduation, 

 and he found that boiling water 

 was generally between 211 and 213, 

 varying with the height of the 

 barometer. Ultimately melting ice 

 was taken as one fixed point and 

 marked 32, and steam rising from 

 water boiling under a pressure of 

 one " standard atmosphere " (760 

 mms. or 29 '92 ins. barometric 

 height) was taken as another and 

 marked 212. In 1742 Celsius of 

 Upsala suggested the centesimal 

 division, and marked the " boiling- 

 point" and the " freezing-point" 

 100. Eight years later Stromer, 

 also of Upsafa, suggested the in- 

 version of the numbers, and gave 

 us the present form of the " centi- 

 grade " thermometer. 



As different liquids did not ex- 

 pand proportionately one with the 

 other on receiving similar altera- 

 tions in hotness, some difficulty 

 was experienced in deciding on the 

 points which were to be marked 

 1, 2, 3, etc., since mercury indi- 

 cated a slightly different series to 

 other suitable liquids such as 

 alcohol, pentane, etc. Through the 

 researches of Boyle and Amontons 

 in the 17th century, of Gay-Lussac. 

 Dalton, and Charles in the 18th 

 and 19th, and of Regnault in the 

 19th century, the expansibility of 

 gases had been very carefully 

 observed, and the notable fact of 

 the very approximate equality of 

 their expansibilities had been 

 clearly enunciated, especially for 



