Robert IIardwicke, 192, Piccadilly, w. 13 



Svo. price Is. 



Vegetable Charcoal. 



Its Medicinal and Economic properties, with practical remarks on 

 its use in chronic affections of the Stomach and Bowels. By James 

 Bird,M.R.C.S. 



Hardwicke's Elementary Books. 



PEICE TWOPENCE EACH. 



Under the above title is presented to the Public a complete Library 

 of Elementary Works adapted for the use of the People. 



Thousands of people at present skilled as handicraftsmen, and as 

 workers in the various arts and sciences of life, work from day to da;. , 

 plodding on with some vague notion that they can improve their own par- 

 ticular calling ; but it generally ends in nothing, because they are ignorant 

 of the first principles of those laws which regulate the things in which they 

 are engaged. It is a very rare occurrence to meet with workmen who know 

 anything beyond what they picked up in their apprenticeship, or obtained 

 by imitating others more skilled than themselves. 



It will be the aim of Hardwicke's Elementary Books to teach 

 these first principles. 



No labour or expense will be spared to make the information of a 

 thoroughly reliable character ; and, where advisable, a free use of authentic 

 illustrations will be brousht to bear. 



i 



i NOW READY :- 



Mechanics. 



The principles of Mechanics and the elements of Machinery. Containing : — 

 Action and reaction — Aerolites — Air, compressed, power — Atmosphere, resistance 

 of — Balance — Balloon, gravitation of — Central forces — Centrifugal force — Com- 

 pound machinery — Cord, multiplied— Cordage, rigidity of — Curved surfaces — 

 Curvilinear motions — Earth, gravitative attraction of — Elasticity — Endless screw 

 — Equilibrium, or rest — Forces, composition of, parallelogram of — Fly-wheels- 

 Friction — Friction-wheels — Fulcrum, the — Gravitation, laws of — Gravity, centre 

 of — Heat as a moving power — Impulse — Inclined Planes — Levers, system of — 

 Machinery, compound — materials, strength of — Mechanical powers — Mobility — 

 Momentum — Motion, accelerated, in curves, on inclined planes, oscillatory, rela- 

 tive, retarded, various kinds of— Moving bodies — Multiplied cord— Oblique action 

 — Orbits, motion of bodies in — Oscillatory motion — Pendulums, compensating, 

 oscillation of, relative lengths of — Percussion, centre of — Planes, inclined — Power, 

 or impulse — Powers, mechanical, moving — Projection of bodies upward — Pulley, 

 the — Pulleys, system of — Resistance — Scales — Screw, the— Stability — Steelyard 

 — Strength of animals, of man, of materials— Treadwheel — Universal joint — 

 Velocity, accelerated, of falling bodies, of moving bodies — Wedge, the— Weight 

 — Wheel and axle, and pinion, fly; friction — Whirling motion of liquids — and 

 much more useful information. Fully illustrated by nearly 100 cuts. Two 

 parts, 2d. each ; complete, 4d. ; bound in c'.oth, 6d. 



