THE ^OUNG SCIENTIST. 
7 
fleeted rays of light will fall into the 
water. A bright spot will be seen at the 
bottom, so light as to show the smallest 
object plainly. By this means we have 
examined the bottoms of wells fifty feet 
deep, when half full or more of water. 
The smallest straw or other objects can be 
perfectly seen from the surface. In the 
same way one can examine the bottom of 
the ponds and rivers, if the waters be 
somewhat clear and not agitated by winds 
or rapid motion. If a well or cistern be 
under cover, or shaded by a building so 
that the sunlight will not fall near the 
opening, it is only necessary to employ 
two mirrors, using one to reflect the light 
to the opening, and another to reflect it 
down into the water. Bright sunlight 
may be thrown fifty or a himdred yards 
each mirror diminishes the brilliancy of 
the light. Let any one not familiar with 
the method, try it, and he will not only 
find it useful, but a very pleasant experi- 
ment. It will, perhaps, reveal a mass of 
sediment at the bottom of a well that has 
been little thought of, but which ma> 
have been a frighlful source of disease by 
its decay in the water. 
Drawing Lessons —Y. 
BY JOHN CLARK CENTER. 
WE will now turn our attention to ex- 
ercises that will require a different 
method of treatment, and develop a quick 
and free use of the hand and pencil. 
The examples of curved lines in Fig. 1 
must be practiced, and the pupil must not 
to the precise spot desirable, and then 
downward. We have used the mirror 
with success to reflect light around the 
house to a shaded well, and also to carry 
it from a south window through two 
rooms, and then into a cistern under the 
north side of the house. Half a dozen re- 
flections of light may be made, though 
rest satisfied until he is able with a single- 
sweep to draw them correctly. He should 
attempt to draw these curves in all manner 
of positions, beginning at the top, then 
at the bottom, and making the curve up- 
wards, and so on, until the utmost facility 
is attained in drawing them, however 
placed. The curved line, known as the 
Fig. 2. 
