+---------------------+------------------+---------------------- | | Boiling point in | Steam pressure above | Solution of soda. | Centigrades. | atmospheric pressure | | | in atmospheres. +---------------------+------------------+---------------------- |100 NaO HO + 10 H2O | 256 deg. C. | 40 atm. | " + 20 " | 220.5 " | 21 " | " + 30 " | 200 " | 15 " | " + 40 " | 185.5 " | 10.2 " | " + 50 " | 174.5 " | 7.7 " | " + 60 " | 166 " | 6.1 " | " + 70 " | 159.5 " | 5.1 " | " + 80 " | 154 " | 4.2 " | " + 90 " | 149 " | 3.6 " | " + 100 " | 144 " | 3.0 " | " + 120 " | 136 " | 2.2 " | " + 140 " | 130 " | 1.6 " | " + 200 " | 120 " | 0.95 " | " + 300 " | 110.3 " | 0.4 " | " + 400 " | 107 " | 0.3 " +---------------------+------------------+---------------------- _Experiment No. 15_.[3]--The boiler of the engine, Fig. 2, was filled with 231 kilogs. water of two atmospheres pressure and a temperature of about 135 deg. Cent.; the soda vessel with 544 kilogs. of soda lye of 22.9 per cent. water and a temperature of 200 deg. Cent., its boiling point being about 218 deg. Cent. The engine overcame the frictional resistance produced by a brake. At starting the temperature of both liquids had become nearly equal, viz., about 153 deg. Cent. The temperature of the soda lye could therefore be raised by 47 deg. Cent, before boiling took place, but, as dilution, consequent upon absorption of steam would take place, a boiling point could only be reached less than 218 deg. Cent., but more than 153 deg. Cent. The engine was then set in motion at 100 revolutions per minute. The steam passing through the engine reached the soda vessel with a temperature of 100 deg. Cent.; the temperature of the soda lye began to rise almost immediately, but at the same time the steam boiler losing steam above, and not being influenced as quickly by the increased heat below, showed a decrease of temperature. The difference of the two temperatures, which was at starting 1.3 deg. Cent., consequently increased to 7.2 deg. Cent, after 17 min., the boiler having then its lowest temperature of 148.8 deg. Cent. After that both temperatures rose together, the difference between them increasing slightly to 9.5 deg. Cent., and then decreasing continually. After 2 hours 13 min., when the engine had made 12,000 revolutions, the soda solution had reached a temperature of 170.3 deg. Cent., which proved to be its boiling point. The steam from the engine was now blown off into the open air during the next 24 min.