DICKENSON — ELECTRICITY. 
271 
It is a very common mistake to suppose that when a 
is spoken into that the actual sound is earned along the wnes 
to the person who is receiving the message. te 
speaks the surrounding air becomes agitated with 'e y .nnute 
waves :-for example; if we throw a pebble into u t o l 
the water all round the place where the pebble touched the sur 
face becomes covered with waves, winch travel along he wate 
in circles to the banks and there give the resisting eanh seve a 
slight concussions A very snmlar thing occurs ^h l e tele 
phone The portion of the instrument into winch « -speak 
called' the transmitter is struck by the little sound waves and 
so made to vibrate. These vibrations are trnstomed ms.de the 
■ ^ currents vibrating at exactly tno 
instrument into , cum; nts which how along the 
same rate. I » e £d at the other end are received and 
r,!dn co°nverted into mechanical vibrations in the ear piece 
again converted ulli son with the currents received. 
whete a pi . j ; vibrations to the air in sound waves 
llns P lil f.^" l ; eC eivesthe message. It is not always the 
again and ■ ■ j ; n the house but it is most decidedly 
pleasantest thmg Q minute you will hear the house-wife 
useful and convent . , ^ t h e nex t asking her lady 
ordering all her ' *“PP h th & ere the othe r evening ana to pro- 
triend it she left H r gm g u t we all know the 
ceed to talk of the lates ° u , ctl . ic m otor of which the fans 
telephone more Oi less. ...... .,„„ed to pump water from a 
are a small example can be the clot hes, clean the 
neighbouring well 01 pon 1, tll0 ic0 cream and to do many 
knives, kneai the bread, chu ' Tho tll i e f is now no 
other things to lighten homehoid ca , ^ ^ window the alarm 
longer dreaded for immedn } j porter’s lodge 
or the stables, lhe servants bun disposed of in a very 
suddenly turned on, the unfor “ D SUDerc eded the old form of pull 
short time. The electric bell h ■ I jjjy i„ the houses of 
bell and has been found most P ell wa iled in, sound does 
lolder climates where everything be a house s 0 f the tropics. 
m travel , e»ly X,m mi *» '!» ££ 
ea by 
The uses 
are , , . 
u*vu — - i i* i,*. t, heir little hearts. 
ilectricity are now made to o home are very numerous 
o which power may be app 1( - ] u „htful mind. And now 
nd will suggest themselves to i h^ do in fche way of light 
laving partly seen what e ec i one 0 f the latest develop- 
-nd power in the house we com t ^ ]ong beell known that 
aents— that of its use as heat - . i roedimll resisting its flow, 
he passage of the current throu D i 
