294 REPORT OF OFFICE OF EXPERIMENT STATIONS. 



This bulletin contains twenty-seven experiments for school study 

 and fifteen experiments for home study. One of the latter, prepared 

 by Prof. H. E. Van Norman, is given herewith: 



Experiment 15. — A study of the influence of cleanliness and cold on the keeping quality 



of milk. 



Select a cow whose udder is not particularly clean and whose sides and flanks have 

 not been cleaned. Milk about a quart or so of milk in the usual way, then stop and 

 brush off the sides, flank, and udder of the cow thoroughly, and wipe the udder and 

 adjacent parts with a damp cloth, not wet enough to drip, then with clean hands and 

 clean dry pail milk another quart or so. 



JIave two clean fruit jars, either pint or quart, washed and scalded; fill one with 

 milk drawn before cleaning the cow, and set it away in pantry, kitchen, or cellar at 

 ordinary room temperature. 



Fill the second jar with milk drawn after brushing and wiping the udder and place 

 the jar in a bucket of coldest well or spring water obtainable. If possible take tempera- 

 ture of each jar of milk, of the water, and the room. At the end of twelve hours taste 

 each lot of milk and make note of its condition as to sweetness and flavor. If you have 

 learned to use the acid test at school, test the two lots by means of it. Your observa- 

 tions will then be more acciirate. Note temperatures of each lot, of room, and of water, 

 then put fresh cold water in pail. If possible the water should be 50° F. or colder. 



Make the examination and notes, and change the water every twelve hours until 

 both lots of milk are noticeably sour. If the work has been properly done there should 

 be from half a day to a day and a half difference in the keeping quality of the two lots 

 of milk. 



The Ohio State Agricultural College is issuing a series of extension 

 bulletins containing numerous suggestions for simple agricultural 

 experiments, such as the following: 



Experiment No. 9. 



Take a small piece of butter in a teaspoon. Heat it with a lighted match. It froths 

 freely but quietly. Try the same experiment with a piece of oleo, if it is available. 

 It does not froth but melts down like grease and cracks and sputters. Renovated 

 butter will do the same. Milk fat is a mixture of a number of fats, some of which are 

 volatilized (turned into vapor) at comparatively low temperature (by the heat of the 

 match) and makes the butter froth. Oleo does not contain these fats. Notice the 

 difference in the odor of the melted butter and oleo. Renovated butter is a rancid 

 butter which has been made over by a process of heating and rechurning. The volatile 

 fats have been driven off by the heating. 



Experiment No. 10. 



Fill a large flower pot with loam which has been thoroughly dried. Weigh the pot 

 and loam with a spring balance (see that it will show ounces, for the weighing must be 

 done accurately). Pour in water very slowly until it runs from the hole in the bottom 

 of the pot. Wait until the water has ceased running. Weigh again and determine 

 the per cent of water the loam would hold. It would be well to know what the flower 

 pot weighed before putting the loam in it. 



Try the same experiment with dry clay or with sand 



The water you see rimning away corresponds to the water that should be taken away 

 from soils by tile drains. 



