DECIMAL CLASSIFICATION 
® 
680 Mechanic trades Amateur man- 
uals 
For bilding trades see 690 
Fine mechanism Instruments of precision 
Watch and clock making 
Catalogs of miscellaneous instruments. Classpecial instruments with their subjects 
Apparatus with wheels or motor mekanisms 
Horology Watch and clock making 
See also in astronomy 520.78 
Clock sistems 
Ancient clocks 
Sundials, water clocks, clepsydras 
Constitutent parts of clocks 
Making and repairing. Tools 
Movements: with weights, with springs Barrels 
Wheels Gears 
Hour wheels, minute wheels 
Striking devices: bels, carillons 
Escapements Balance wheels Springs Pendulums 
Regulating devices 
Bearings: friction and lubrication 
Adjusting Regulating 
Repairing 
Watchmakers implements 
Clocks 
See also 681.115 Pneumatic clocks, 681.116 Electric clocks 
House clocks 
Tor clocks considerd as artistic furniture see 749 
Astronomic clocks 
Public « Tower clocks 
Strassburg clock 
Musical clocks 
Drawing room clocks 
Travel clocks 
Alarm “ 
Watches Chronometers 
Fo watche considerd from viewpoint of artistic watchcases see 739 
Watches for ordinary use 
“ with second hands 
Repeater watches 
Chronometers for ordinary use 
Marine chronometers 
Pneumatic clocks 
Motor clocks Canalization 
Receiving clocks: public or private 
Electric clocks Standard clock sistems 
Distributing regulators 
Sistem for transmitting time at a distance 
Sistems of direct transmission 
Minute receivers