2 SCIENCE PROGRESS. 



practice ; on agriculture and medicine the practical appli- 

 cations of biology, and on manufactures and engineering 

 the practical application of physics and chemistry. Whether 

 we are using the ether to transmit energy to ploughs, or 

 measuring the irregular energy of the tissues of a patient 

 by a thermometer, or taking nails out of wheat with 

 magnets, or determining the physical changes produced 

 in materials by small amounts of impurities, we require 

 to understand physical science, and any day some advance 

 in it may be of service in practice. The connections, the 

 railways, the nerves, in this department, are fairly well 

 supplied by the technical journals, but on the purely 

 scientific side there is risk that an undue development 

 of specialisation, without sufficient nourishment and com- 

 munication from other parts, may lead to local turgescence 

 and inflammation, to the injury of the system and the ulti- 

 mate atrophy of the parts. 



In treating of the connections of physical science with 

 other branches of science, we may either divide physical 

 science in some systematic way, and study the connec- 

 tions of each division with other sciences, or begin by 

 considering- the other branches of science and see how each 

 is connected with physical science. Without some syste- 

 matic and rational method, we are sure to omit outlying 

 and unfamiliar parts of any subject of investigation. It is 

 possible in the compass of a short article to go over 

 only a very small number of the various connections 

 between physical science and science in general, and 

 no one individual could do justice to the theme ; it 

 is only possible here to make some suggestions as to 

 methods of systematic division of the subject, and to 

 point out a very few of the connecting links that at 

 present cry for strength. Physical science may generally 

 be described as the study of the properties of matter, 

 energy, and ether. It is divided from chemistry by being 

 the study of each kind of matter by itself, while chemistry 

 studies the actions of different kinds of matter upon one 

 another. Of course no real line can be drawn, and the 

 enumeration of the objects of physical study is for the 



