TRANSACTIONS OF SECTION B. 513 
7. A Colour Reaction for Methylfurfural and its Derivatives. 
By H. J. H. Fenton, £.2.S., and J. P. Mituineton, B.A. 
When bromo-methylfurfural is heated with dimethylaniline and a de-hydrat- 
ing agent, such as phosphorus oxychloride, zine chloride, or dry oxalic acid, an 
intensely blue-coloured compound is obtained, This reaction is extremely sensi- 
tive, and is given by bromo-, chloro-, iodo-, or acetoxy-methylfurfural, and by 
methylfurfural itself, but not by the condensation products previously described.! 
Asa dye the blue colour appears to be very permanent in the dark, but slowly 
fades in sunlight. 
8. A Reaction for Keto-hexoses. By Henry J. Horstman Fenton, F.R.S. 
By oxidation of levulose, cane sugar, inulin, or sorbose in presence of ferrous 
iron at about 90°-100°, and heating the resulting solution with phenylhydrazine- 
p-sulphonic acid, a compound is obtained which dyes silk a rich brownish pink 
colour, which is remarkably stable and permanent. This reaction appears to 
be especially characteristic of keto-hexoses or substances which yield them on 
hydrolysis, and is given by dextrose, milk sugar, maltose or starch only to a 
limited extent, or not at all. 
9. On the Energy of Water and Steam at High Temperatures. 
By Professor C. Dieterict. 
The author has devised a method for determining the specific heat of water at 
temperatures up to 300°C. The water is enclosed in quartz tubes, which are 
sufficiently strong to withstand the pressure of steam—namely, about 100 atmo- 
spheres at 300° C.—and the determinations are made with the aid of the ice 
calorimeter. The results obtained may be expressed by the formula 
e = 1:0160 — 0:0,6057¢ + 0:0,430222, 
in which the specific heat, ¢, is given as a function of the temperature. The 
formula holds between 50° and 300’ C., but does not hold below 50° C., because 
at such low temperatures the point of maximum specific heat first observed by 
Rowland occurs. 
The observations made with water completely enclosed in a tube give the 
difference between the energy of the liquid water at ¢° C. and that of the water 
at 0° C. Since the heat of evaporation is known or calculable, this quantity, 
diminished by the external work, gives the energy difference between saturated 
steam and liquid water at ¢° C. 
Very careful observations have been published by Sir W. Ramsay and 
Professor 8. Young (‘ Phil. Trans.,’ 1891) on the pressure of unsaturated steam 
between 140° and 270°; and since the relation between energy change and 
volume at constant temperature is given by the equation 
A Gy 
Ov/T Or] v 
of the mechanical theory of heat, the change of energy of superheated steam 
depends only on the pressure, and can be calculated from the author's present 
observations. It is, therefore, possible to calculate the energy isothermals and to 
draw the isothermal lines for water. 
After applying the most accurate methods of calculation possible to the new 
observations, the author draws the following conclusions :— 
At about 200° C. the specific heat of superheated steam at constant volume is 
0°5, and is practically independent of the volume if the latter is much greater 
- 1 Fenton and Gostling, Zrans. Chem. Soc., 1899, 423, and 1901, 807. 
1904. LL 
