IX. ANTHROPOLOGICAL. 955 



citation is caused by means of an induction coil. Previous to the freeing of 

 the glass plate, and at the commencement of its motion, the current from the 

 pile is interrupted, because it has to pass through the small insulated spring 

 placed underneath the frame, and through the frame itself. But the latter 

 has fixed to its under edge, on the right-hand side, a small ivory plate, which 

 interrupts the metallic continuity. The excitement takes place just as the 

 frame commences, in its motion, to touch with its brass surface this spring. 

 An instrument fixed to the rod which carries the muscle enables the hori- 

 zontal and the curved line of the muscle to be traced during the same 

 experiment. 



38O6. Muscular Balance. 



Prof. Theodore Schwann, Liege. 



This apparatus was exhibited to the meeting of German naturalists at Jena 

 in 1836. It is intended to demonstrate that muscular contraction takes place 

 in accordance with the laws of elastic bodies. At that time the means of 

 producing the continuous contraction of a muscle were not known. In 

 order to determine the degree of contraction without a load or with increasing 

 loads, the beam of the balance was lowered by means of a screw until the 

 muscle could scarcely bear the load. " It was the first time," says M. Du 

 Bois Reymond (Mem. de 1'Acad. de Berlin, 1859, p. 79), "that an evidently 

 " vital force was investigated in a similar manner to a physical force, and 

 " that the laws of this force were mathematically expressed in figures." The 

 description of the apparatus is also to be found in J. Miiller's Physiology, 

 edition of 1840, Vol. II., p. 59. 



IX. ANTHROPOLOGICAL APPARATUS. 



3999. Anthropological Instruments. 



Messrs. L. Mathieu and Son, Paris. 



1. Anthropological truss. 



2. Metrical measure, leather, divided into inches and centimetres. 



3. Metrical measures, steel, divided into inches and centimetres (2). 



4. Double metre, with articulated springs. 



5. Two large squares, graduated, by M. Broca. 

 G. Facial goniometer 



7. Median 



8. Maxima frame. 



9. Flexible auricular square, by M. Broca. 



10. Plumb line. 



11. Dermographic pencils, by Piorry. 



12. Pocket dynamometers, by Mathieu. 



13. Pneumometer, and pneumodynamometer. 



14. Sphygmograph, by M. Marey. 



15. by Meurisse and Hy. Mathieu. 



16. Anthropometer. 



17. Graduated plane, by M. Broca. 



18. Profilometer, by Sauvage. 



19. Directing and exploring square, by M. Broca. 



20. Meter, brass. 



21. Caliper compasses, by M. Broca. 



22. Micrometric caliper compasses, by M. Broca. 



23. Cylometer 



