Introduction. 9 



cauterizing. These three forms of application of the electric current were, 

 irrespective of constant improvements made in their own department, greatly 

 encouraged by the general progress of electrical engineering, in particular, 

 however, by the recent utilization of accumulators for therapeutical purposes; 

 quite recently it has even become possible to charge these comparatively small 

 accumulators by means of a thermo-pile, which greatly reduces the inconvenience 

 attending the use of other sources of electricity. Electro-therapeutical appliances 

 are chiefly made in Berlin, Francfort o/M. und Erlangen. 



Physiological instruments also occupy a wide space. We may specially 

 allude to the ophthalmological instruments, in particular, to Helmholtz's. ophthal- 

 moscope, which since its invention has undergone many modifications. 



The manufacture of didactic apparatus has reached a considerable 

 extension, owing to the stress which is laid by modern educational training 

 upon ocular demonstration; not only science colleges and advanced public 

 schools are, accordingly, provided with well equipped laboratories, but also in 

 elementary schools the possession of an adequate amount of apparatus for pur- 

 poses of demonstration is deemed imperative. The German educational appara- 

 tus, which are extensively used in all parts of the globe, satisfy three impor- 

 tant conditions: they are very cheap; they are so dimensioned that all their 

 parts may be easily demonstrated; they are made in their simplest possible 

 form all those details which are necessary only for exact measurements being 

 omitted. 



The extensiveness of the German watch and clock manufacture is a 

 well-known fact. The manufacture of the so-called ,,Schwarzwald" clock gives, 

 in Wuerttemberg and Baden alone, employment to 101 firms. The manufacture 

 of regulators, watches, tower-clocks and watches and clocks for special pur- 

 poses gives work to 51 of the larger establishments; the finest astronomical 

 chronometers and thermometers are naturally only made by a few clock- 

 makers; the reputation of these, however, is far spread. 



We will supplement this condensed sketch of the extent of the German 

 instrument manufacture by a few remarks on the technical means employed. 

 German makers utilize largely, by critical selection, numerous new, principally 

 American, inventions in tool-making, but, generally speaking, they prefer to 

 make their own tools according to their special requirements. German makers 

 require, therefore, perhaps rather more time for their productions than their 

 foreign competitors; the process of manufacture bears also little resemblance 

 to whole-sale manufacture and the system of division of labour is only imper- 

 fectly adopted; possibly we may find in these very facts the explanation of the 

 individuality of the German instruments. 



The commercial value of the German scientific and optical instrument 

 trade is in correspondence with its scientific reputation. This fact will be 

 readily gathered from the following table showing the German export to 

 America, Australia, China and Japan during the last three years: 



