ChemWatch is the best source for Material Safety Data Sheets (MSDS) of chemicals held at the University of Canterbury.
The Biofuels Handbook by 
CRCnetBASE
Consists of a compilation of essential engineering information, including data, facts, figures, graphs, equations, illustrations, and charts. It covers the disciplines of aerospace engineering, civil engineering, electrical engineering, electronics, general engineering, industrial engineering management, machine design, mechanical engineering, packaging, biomedical engineering, computer engineering, electrical engineering communications, engineering management, industrial engineering & manufacturing, lasers & optical engineering, manufacturing processing, nanoscience/nanotechnology and system engineering.
McGraw-Hill Concise Encyclopedia of Science and Technology by 
McGraw-Hill Dictionary of Scientific and Technical Terms by 
McGraw-Hill's Engineering Companion by 
Chemical Engineer's Condensed Encyclopedia of Process Equipment by 
CRC handbook of Chemistry and Physics
A ready-reference book of chemical and physical data
Perry's Standard Tables and Formulae for Chemical Engineers by 
Van Nostrand's Encyclopedia of Chemistry by 
