( ( ( ( ( His ( two books ) ) , ) ( ( Thermodynamics and ) ( ( ( the ( Free Energy ) ) ( of ( ( ( ( ( ( Chemical ( Substances ( McGraw-Hill -RRB- ) ) ) , ) and ) Valence ) and ) ( the Structure ) ) ) ) ( of ( ( ( Atoms and ) Molecules ) ( -LRB- ( Dover -RRB- ) ) ) ) ) ) ) , ) ( ( ( were both ) ( published ( in 1923 ) ) ) . ) )
(ROOT (S (NP (NP (PRP$ His) (CD two) (NNS books)) (, ,) (NP (NP (NNP Thermodynamics)) (CC and) (NP (NP (DT the) (NNP Free) (NNP Energy)) (PP (IN of) (NP (NP (NNP Chemical) (NNP Substances) (NNP McGraw-Hill) (-RRB- -RRB-)) (, ,) (CC and) (NP (NNP Valence)) (CC and) (NP (DT the) (NN Structure)))) (PP (IN of) (NP (NP (NNPS Atoms) (CC and) (NNPS Molecules)) (PRN (-LRB- -LRB-) (NP (NNP Dover)) (-RRB- -RRB-)))))) (, ,)) (VP (VBD were) (DT both) (VP (VBN published) (PP (IN in) (NP (CD 1923))))) (. .)))
His two books, Thermodynamics and the Free Energy of Chemical Substances McGraw-Hill), and Valence and the Structure of Atoms and Molecules (Dover), were both published in 1923.
(ROOT (S (NP (NNP Energy)) (VP (VBZ is) (VP (VBN stored) (PP (IN in) (NP (NP (DT a) (JJ chemical) (NN substance)) (PP (IN between) (NP (NNS atoms))))))) (. .)))
Energy is stored in a chemical substance between atoms.