602 



EXPERIMENT STATION RFCORD. 

 III. THE CARBOHYDRATES.' 



The heat equivalent of the so-called caiboliydrates is g^iven in the 

 following table. All these results are from combustions made with the 



bomb : 



Heat of comhHsllon of carholtydrates. 



Substance. 



Pentoses: 



Arabiiiose 



Xylose 



Khamnose 



Khamuose (crystallized) 



Tucose .' 



Hexosea: 



6-Glucose 



S-Frnct ose . . .'. 



Galactose 



Sorbinose 



Disaccliarids: 



Cane sugar 



Millv sugar 



Milk sugar (crystallized) 



Maltose 



Maltose (crystallized) . . . 



Trehalose 



Trehalose (crystallized) . 

 Trisaccharids: 



Meljtose 



Melitose (crystallized) . . . 



Melicitose 



Polysaccharids : 



Glycogen 



Cellulose 



Starch 



Dextrau 



luulin , 



Composition. 



CsH.oOs 



C,,H,o05 



C,H,,0, 



CBH12O5.H2O 



CuH.jOs 



CgH,,06 



CfiHiA 



CfiHijOs 



^r.UiaOg 



CijHj.^Gii 



CiiHjjO,! 



C,.,H.,20„.H,0 



C12H2.2OU 



Ci-2aI220||.H^>0 



CijHjjOi] 



Ci2H220ij.2H20 



CisHj.jOjo 



CisH320i6.5H,0 



*^18H340|7 



(Cr.H,A)x 



(C,iH,o05)x 



(r,H,„05)x 



(CfiH,o05)x 



CsoHfijOsi 



Molecular 

 weijrlit. 



Heat equivalents. 



150 

 150 

 164 



J 83 

 164 



180 

 180 

 180 

 180 



342 

 342 

 360 

 342 

 300 

 343 

 378 



504 

 504 

 522 



(162)x 

 (162)x 

 (162)x 

 (162)x 

 990 



Large cal- 

 ories per 

 gram mole- 

 cule. 



558.3 

 561.9 

 718.5 

 711.8 

 712.2 



673.7 

 675. 9 

 G69. 9 

 668.6 



1, 352. 7 

 1,351.4 

 1,345.2 

 1, 350. 7 

 1, 339. 8 

 1,349.9 



1, 345. 3 



2, 026. 5 

 2,019.7 

 2, 043. 



678.9 

 678 

 677.5 

 6G6.2 

 4, 092. i 



Small 



calories 



per 



eram. 



3, 722. 



3, 746. 

 4,381.1 

 3,911.0 



4, 342. 7 



3, 742. 6 

 3, 7.55. 

 3, 721. 5 

 3, 714. 5 



3, 955. 2 

 3, 951. 5 

 3, 736. 8 

 3, 949. 3 

 3,721.8 



3, 947. 

 3, 550. 3 



4, 020. 8 

 3, 400. 2 



3, 913. 7 



4, 190. 6 

 4,185.4 

 4, 182. 5 

 4,112.3 



4, 133. 5 



Ehamnose and fucose were included in this list after careful cousid- 

 eration. Botli have the composition CHl-O.,, and are not members of 

 the same group as the others. Though they are pentoses they differ 

 from tlie others in having a methyl group in place of one liydrogen.atom. 



Quite a number of the compounds given in the last table were burned 

 earlier by the potassium chlorate method. The results by the two 

 methods are compared below: 



Ilesulis of comuusUons hy the oxygen and potassium chlorate methods. 



Oxygen 

 method. 



Potasisium 

 chlorate 

 method. 



Ratio of 

 results by 



two 

 methods. 



8-Glucose 



Galactose 



A rabinose 



Cane sugar 



Milk stigar 



Milk sugar (crystallized) 



Melitose ! 



Cellulose 



Starch 



luuliu 



Calories. 

 673.7 

 609. 9 

 558.3 



1, 352. 7 

 1,351.4 

 1,345.2 



2, 026. 5 

 678.0 

 677.5 



4, 092. 1 



Calories. 



064.6 



658.6 



554. 2 



1, 322. 2 



1, 325. 9 



1,318.7 



1,979.7 



071.7 



667.9 



4, 029. 3 



98.64 

 98.31 

 99.27 

 97.74 

 98.11 

 98.03 

 97.69 

 99.07 

 98.58 

 98.47 



I Jour. jH-ak. Chem., 2a ser., 31, p. 285 ; 15, p. 305. 



