PREFACE. The present book is more than a revision of my Process Digest, since it is entirely rewritten, all the cases being reread from the point of view of an attorney and expert witness, instead of that of a Patent Office Examiner. For this reason there are specific notes on the kind of evi- dence needed in chemical and allied cases, and also notes covering the cases on damages, licenses, etc. No attempt has been made to criticize any decision or the findings on which it is based. The book is intended as a statement of the law, with a practically complete finding list of the cases on which the law of chemical patents is based, and it also in- cludes the principal cases intimately related in reasoning to such cases. While errors will undoubtedly be found it is believed that they are only such as are easily recognized. I only regret that, unlike Eobinson, I have not the leisure needed to spend two years in rereading and veri- fying every cited case. Cases are cited, from the reports...