Ill 
No. XV.—MACHINERY, 
The use of machinery, even in its simplest form and moved 
by manual power, may be regarded as a sign that the people 
employing it have already emerged from the lowest stages of 
civilization. The transition, for instance, from the use of a 
pair of rubbing-stones or “ saddle-quern ” to that of a pair of 
millstones, one of which revolves and is driven by hand (the 
ordinary quern), is a great step in advance ; but machinery 
can hardly be said to have been thoroughly introduced into 
a country until some of the forces of Nature, such as those of 
wind and water, have been utilized as motive power. The 
windlass, the common pump, the potter’s wheel (No. XL), 
the revolving hand-mill, the spinning-wheel (No. IX.), 
the turning-lathe, and some forms of looms (No. VII.) may 
however, be regarded as machines, as they are mechanical 
means of economizing human labour. 
The earliest and simplest application of hydraulic power 
appears to have been for purposes of irrigation, and in some 
countries the use of water-power appears to be almost re- 
tricted to this purpose. The following questions are sug¬ 
gested :— 
1. Are revolving millstones in use? if so, describe their 
form, the manner in which driven, and the purposes to which 
applied. 2. What kind of stones are used for this purpose ? 
and of what materials are the pivots and bearings formed ? 
3. Are pebbles with a conical socket in them used as bearings 
for the pivots, or are the pivots made of stone ? 4. Are any 
pounding-mills in use, or any mechanical means employed to 
assist the motion of pestles in mortars ? 5. Are any forms 
of rolling-mills employed for crushing purposes ? 6. Is any 
form of turning-lathe in use, and of what kind ? is the rotary 
motion continuous or alternate ? 7. How are the turning- 
tools applied ? and what is their character ? 8. What articles 
are turned 1 9. Is the common windlass in use ? and for 
what purposes % 10. Is any form of pump in use ? if not, 
