The chemistry of housework is a subject so varied that new problems arise almost every day and new methods of attacking old gems are constantly to be discovered. This complication, a few underlying principles are unalterableand will help us to right conclusions. These lessons are by no means complete and an experienced housekeeper will think of many questions which are unanswered and methods of work that she herself employs which are not mentioned here. I hope that you will tell me of your own methods and experiences and I especially want you to ask questions so that we may supplement the lessons together. Many of the subjects which are only touched upon in this series are taken up fully from a different standpoint in later lessons. I am indebted to my revered friend and teacher, Mrs. Ellen H. Richards, for the suggestion of the treatment of the subject in the order of A Days Chemistry and for the use of material in her published books. There is no BEST rule of universal application for circmstances vary so widely, but the reason why some methods produce good results are here set forth. In the study of these lessons I would advise taking up one subject at a time, illustrating it by the experiments suggested and by others which may occur to you. After considering each topic in detail in this way, read the whole lesson-over carefully. When puzzled over anything, make a note of the difficulty and if you do not discover an explanation for yourself, write to the School for assistance. As you know from your own experience, work that really interests does not prove as fritiguing as mere drudgery. An intelligent interest in the reason any of daily happenings will surely make your daily duties go more easily and may lead you to discover simpler and more effective methods. And so I wish you much success and pleasure in following this brief study of A Day Chemistry......