FARMERS' INSTITUTES. 



161 



BOILING POINT. 



Boiling 

 point, water. 



Beg. 

 Fahrenheit. 



32 

 100 

 126 

 150 



175 

 185 

 190 

 194 



200 

 202 

 205 



210 



210.25 



210.5 



211 



211.0 



212 



212.5 



213 



222.4 



230.5 



244.3 

 250.2 

 275.7 

 300.8 

 337.8 



Barometer 

 inches. 



M8 

 1.94 

 4. 

 7.69 



13.45 

 17.16 

 19.13 



20.82 



23.. J9 

 24.58 

 26.11 

 27.73 



28.85 



29. 



29.15 



29.42 



29.71 



30. 



30.30 



30.59 



36.90 



42.34 



55.08 

 60.65 

 92.66 



Pressure, 

 lbs. per sq. 

 inch above a 



.08 

 .95 



3^78 



6.60 

 8.37 

 9.40 

 10.00 



11.80 

 12.00 

 13.. 50 

 13.70 



14.12 

 14.21 

 14.28 

 14.42 

 14.56 



14.7 

 Steam 

 gauge 



3.3 lbs. 



6.3 



12.3 

 15.3 

 31.3 

 .53.3 

 100.3 



Altitude feet 



above 



sea Itvel. 



35,000 



20,740 

 14,649 

 11,799 

 9,579 



6,304 

 5,225 

 3,642 

 2,063 



1,025 

 834 

 754 

 512 

 255 



-261 

 —511 



-6,000 



Remarks. 



Temp, at -which water boils and freezes. 



Temp, milk is conden.=ed. 

 Glaislus altitude in balloon. 



Approx. height, Alaska Mountains. 



Altitude, Quito, S. A. 



Altitude, Denver, Col. 



Max. altitude, Michigan, Porcupine mountain. 



Altitude, Michigan Agricultural College. 

 Altitude, Detroit, Mich., 578. 



Sea level. 



I Temperatures and pressures used in process 

 I canning. 



An examination of this table shows why water boils at 210 here. 

 Levels run over the railroads show that we are about 1,000 feet above 

 sea level, and then we know the average height of the barometer is 29 

 inches, and if we were to go up higher the boiling point would keep 

 getting lower. A temperature of over 200 degrees is necessary to 

 properly prepare almost everything we are in the habit of having boiled. 

 Glaisher went up in a balloon to a height where water boiled at 148 

 degrees. He would have had a hard time preparing a boiled dinner. On 

 the high mountains, people resort to various schemes to raise the boiling 

 point so that they can boil meats or steep tea; one is placing salt or soda 

 in the water, another is that of using a tightly fitting cover so that the 

 kettle is in reality a small steam boiler. It is said that they set the 

 safety valve on such cookers to correspond to the age of the chicken. 

 Another application of change of pressure is in one of the sugar pre- 

 serves — it represents one of Michigan's industries, the condensed milk. 

 Milk cannot be successfully boiled down to a temperature of 210 or 212. 

 Experience has fixed the boiling point for milk at 128 to 130 degrees. 

 Boiling at this temperature would be an easy matter 8 or 10 miles 

 above us. But at Lansing they accomplish this result by use of an air 

 pump connected to a closed pan. Fifteen thousand pounds of milk is 

 placed in a pan and it is made to boil furiously, yet at any time one could 

 place his hands in the pan without discomfort. Usually in three hours 

 they drive off 12,500 pounds of water, leaving 2,500 pounds of milk, to 

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