RECENT PROGRESS IN CHEMISTRY. 537 



the diverse matters grouped under the term chemical engineering. Of 

 this very practical branch of chemical science, as well as of the valua- 

 ble additions to materia medica, of the improved methods introduced 

 into analytical chemistry, and of the contributions to the chemistry 

 of agriculture, no mention can be attempted. 



The tendency of modern researches in chemistry is to magnify the 

 atomic theory ; the rapid accumulation of facts, the ever-increasing 

 ingenious hypotheses, the most searching examinations of co-ordinate 

 laws, all tend to strengthen the Daltonian adaptation of the philo- 

 sophic Greeks. Here and there a voice is raised against the slavish 

 worship of picturesque formulae ; but, against the molecular theory 

 underlying the symbolic system so depicted, few earnest arguments 

 are advanced. The whole aim of organic chemistry is directed to the 

 discovery of the arrangement of atoms within the molecule, and the 

 success Obtained justifies the hypothesis. The edifice erected through 

 these achievements, though young in years, is too substantial to tol- 

 erate displacement of its corner-stone. The absolute truth of the 

 atomic theory is beyond man's power to establish ; even admitting 

 that it necessitates absurd assumptions, it is, nevertheless, indisputably 

 the " best existing explanation of the facts of chemistry as at present 

 known." 



A noteworthy feature of existing chemical research is the recog- 

 nition of the necessity of a more intimate knowledge of the connection 

 between physical characters and chemical constitution. In the past 

 chemists increased the number of new compounds so rapidly that they 

 often neglected detailed examination of their physical properties, their 

 relations to known bodies and to each other, preferring to satisfy their 

 ambition by fresh discoveries. This race after new bodies still con- 

 tinues, but parallel with it are zealous investigators striving after a 

 knowledge of the innate qualities and bearings of these same bodies ; 

 and the latter class of students is gaining prizes no less valuable than 

 those secured by the former. 



Chemists are also recognizing the necessity of a more minute study 

 of the simpler phenomena of chemistry, and it is in this direction that 

 they look for many laurels in the future. Priestley's day of great dis- 

 coveries by the simplest means has in one sense passed ; the opportuni- 

 ties for isolating nine new gases, or of recognizing by chemical tests 

 half a dozen new elementary bodies, in the space of a lifetime, are 

 gone ; only by the employment of the most delicate appliances, by the 

 closest scrutiny of phenomena and the conditions governing them, by 

 availing themselves of all the resources of physics, by an unshrinking 

 expenditure of time and of money, to say nothing of the necessity of 

 trained mental powers of no low order and of skilled hands, shall chem- 

 ists in succeeding generations realize their ambitious designs. 



