I feel thoroughly satisfied in presenting the twentieth
Edition of this popular book in Multicolour. The present
edition of this book has been thoroughly revised and a lot
of useful material has been added to improve its quality
and use. It also contains lot of pictures and coloured
diagrams for better and quick understanding as well as
grasping the subject matter.
I am highly obliged to my son Mr. N.P.S. Khurmi
B.Tech (Hons) for his dedicated and untiring efforts to
revise and bring out the book in its present form.
Although every care has been taken to check mistakes
and misprints, yet it is difficult to claim perfection. Any
error, omission and suggestion for the improvement of
this volume, brought to my notice, will be thankfully
acknowledged and incorporated in the next edition.
B-510, New Friends Colony, R.S. Khurmi
PREFACE TO THE TWENTIETH