DUST GARDENS, 
7 
in the laundry basket are mildewed; the “best room,” 
seldom used and darkened by drawn shades and tight¬ 
ly closed blinds, becomes musty. 
What do all these things mean, or have they any re¬ 
lation to each other? 
We will now see if we can answer these questions. 
Experiment I. Mix a little yeast with some sweet¬ 
ened water and let it stand in a warm place where the 
temperature is from 70° to 75 0 Fahr. Put a few table¬ 
spoonfuls of beef broth or molasses water into a cup 
or bottle and leave it uncovered in the kitchen where 
it will be warm. Watch carefully what happens. Be¬ 
fore long bubbles show on the surface of the sweetened 
water; perhaps you may see bubbles rising in the broth. 
If left long enough the sweet liquid will be sour and 
the good broth smell bad. You say the one has fer¬ 
mented, the other is putrid. What has made the 
change? You did not add anything to the mixture; 
you only kept it warm and uncovered. 
DUST GARDENS. 
Experiment II. From any dealer in laboratory sup¬ 
plies or through the doctor or druggist get a Petri dish 
or plate. This is simply two round glass dishes, one- 
quarter to one-half inch in depth, one just large enough 
to fit over the other as a cover. See Fig. 1. This ex¬ 
periment can be made without the Petri dish, although 
not so conveniently, as follows: 
Take a clear glass sauce dish or a finger bowl. Fig. 
2. Cover with a piece of smooth, thin glass clear 
Experiments 
with Dust 
The Garden 
Plot 
