1900, Oscar Oldberg, Inorganic General, Medical and Pharmaceutical Chemistry, Chicago Medical Book Company; Volume I, Part III, Chapter LXVIII, page 479:It is possible to know something of theoretical chemistry, and to even do some successful and correct laboratory work in chemistry by strictly obeying the directions laid down in reliable books, without possessing a thorough mastery of the construction and use of chemical equations and of stœchiometry ; but the chemical work done by operators who can not of their own knowledge and skill write and balance chemical equations and make correct stœchiometric calculations must always be untrustworthy.