182 



THE IRRIGATION AGE. 



wooden float and wire broom, by which means there 

 is afforded perfect footing for horses. At intervals 

 of 25 feet the road is divided into sections by nar- 

 row contraction joints extending crosswise the road 

 and entirely through the concrete. These joints are 

 formed by means of a thin metal or wooden cross- 

 form or divider to which is tied a single or double 

 thickness of tar paper with the paper face against 

 the last laid section of roadway. After the surface 

 of this section is finished, and while the concrete for 

 the adjoining sections is being placed, the cord hold- 

 ing the paper to the cross-form is cut and the cross- 

 form is removed. The tar paper adheres to the con- 

 crete and stays in the joint, which is reduced to the 

 thickness of the paper by forcing against it the 

 freshly placed concrete of the section under con- 

 struction. 



When the surface of the concrete has hardened 

 enough to prevent pitting it is sprinkled with clean 

 water and is kept moist for several days. Likewise, 

 as soom as possible, the pavement is covered tempo- 

 rarily with two inches of sa'nd or dirt from the side- 

 road to give further aid in curing the concrete. 

 Traffic is confined to the earthen side-roads until 

 the concrete is about two weeks old. In the mean- 

 time shoulders of broken stone or gravel are built 

 along both edges of the pavement. These are made 

 three feet wide and sufficiently thick to be firm and 

 to make it an easy matter at all times for wagon 

 wheels to pass from the side-road onto the pave- 

 ment. 

 The First Cost and the Real Cost of Roadways. 



There are two phases of the cost of any im- 

 provement first cost and up-keep expense. In both 

 items the concrete road has proven less expensive 

 than any other kind of permanent roadway. Of 

 some three million yards of city and country con- 

 crete pavements built in recent years, the average 

 first cost has been $1.22 per square yard. The annual 

 up-keep expense per mile on these roads has been 

 almost nothing. In Bellefontaine, Ohio, concrete 

 pavements in use 18 years have cost annually for 

 maintenance only % of one cent per square yard. 

 Up-keep cost of Wayne County, Michigan, country 

 concrete roads for three years has averaged but 

 $2.50 per mile. In 1911 the mean cost of repairing 

 macadam roads in New York state was $800.00 per 

 mile 10 per cent of the first cost. If these roads 

 had been concrete, practically all this immense ex- 

 pense could have been saved and used in building 

 new roads instead of repairing old ones. With bet- 

 ter roads will come better schools, better churches, 

 happier homes, better business and decreased cost 

 of living. 



DIRECTIONS FOR OPERATING THE BAB- 

 COCK TEST. 



The Babcock Test is a means of determining 

 the percent of fat in milk, cream and other dairy 

 products. The tester is a machine which separates 

 the fat from milk by centrifugal force and brings it 

 into the graduated neck of the milk bottle, so that 

 the per cent of fat in the milk may be read directly. 

 The equipment consists of the tester proper, called 

 the centrifuge, a 17.6 c.c. pipette, milk and cream 

 test bottles, an acid measure, a quantity of sulphuric 

 acid, and a pair of dividers. A complete two-bottle 



outfit, suitable for farm use, can be purchased for 

 about $4.00. 



In making the test, great accuracy is required. 

 Before taking a sample, the milk should be well 

 mixed by shaking. If the milk is cold, it should be 

 warmed in water heated to about 110 degrees Fahr., 

 then shaken thoroughly or poured back and forth 

 from one bottle to another, so that butter fat may be 

 thoroughly mixed with the milk. The 17.6 c.c. pi- 

 pette should be inserted immediately and the milk 

 sucked to a little above the mark on the neck of the 

 pipette. The right forefinger can be placed quickly 

 over the top of the pipette to hold the milk. If the 

 finger is dry, the pressure may be released to allow 

 the milk to run down until even with the mark. The 

 milk should then be transferred without loss to the 

 milk bottle. This can be done most easily by hold- 

 ing the bottle in an inclined position and allowing 

 the milk to run down the side of the bottle neck. 



Sulphuric acid of specific gravity of 1.82 to 1.83 

 should be added. The amount to use is 17.5 c.c. 

 The acid measure is marked to indicate that amount. 

 If too little acid is used or the acid is too weak, the 

 casein will not be all dissolved, and the test will be 

 spoiled. If the acid is too strong or too much is 

 used, the casein will be burned and black charred 

 substances will intermix with the fat. In adding 

 the acid, the test bottle should be held in an inclined 

 position and the acid allowed to run down the side 

 of the bottle. The acid, being heavier than milk, 

 goes to the bottom and forces the milk up. Shake 

 the bottle immediately with a rotary motion until 

 the acid and milk are thoroughly mixed. The action 

 of the acid is to dissolve the solids-not-fat in the 

 milk. The chemical action causes the mixture to 

 become very hot and almost black in color. 



'While still hot, the bottles should be placed in 

 the centrifuge and whirled at the proper speed. Dif- 

 ferent machines require different speeds, and one 

 should follow the directions that accompany the out- 

 fit. The required speed may vary from 800 to 1,200 

 revolutions of the wheel per minute, according to 

 the diameter of the wheel. After whirling for five 

 minutes, the machine should be stopped and hot 

 water of a temperature of 140 Fahr. should be put 

 in in sufficient quantity to bring the fat up to the 

 neck of the bottle. Then whirl for two minutes 

 more and add water to bring the fat all within the 

 graduated portion of the neck. Whirl again for one 

 minute, to make sure all the fat has come into the 

 bottle neck and to clarify the line between the fat 

 and the water. 



The fat as it appears in the neck of the test bot- 

 tle should have a yellowish or straw color, and be 

 clearly distinct from the water below. Any black 

 or flocculent matter in or at the edge of the fat col- 

 umn should not occur if the test is conducted prop- 

 erly. 



The reading should be taken while the bottles 

 are still hot; 125 to 140 Fahr. is the temperature 

 at which the readings should be made. If the bot- 

 tles cool before the reading is made, they should be 

 placed in a water bath of the required temperature 

 and then read. To read the test, the dividers are 

 used, placing one point at the BOTTOM of the fat 

 column and the other at the extreme TOP. Then, 

 without changing the angle of the dividers, they are 



