RECOMMENDATIONS. 491 



2. The atomic weight of bodies. 



3. List of the metals, with columns for specific gravity, — 

 electricity, — tenacity, — specific heat, — conducting power for 

 heat, — conducting power for electricity, — melting point, — re- 

 fractive power, — proportion of rays reflected out of 1000, — at 

 an incidence of 90°. 



4. Specific gravities of all bodies. 



5. List of mammalia, with columns for height, — length, — 

 weight, — weight of skeleton, — weight of each bone, — its great- 

 est length, — its smallest circumference, — its specific gravity, — 

 number of young at a birth, — number of pulsations per minute, 

 — number of inspirations per minute, — period of blindness after 

 birth, — of sucking, — of maturity, — temperature, — average du- 

 ration of life, — proportion of males to females produced, &c. &c. 



After enumerating twenty such general heads of Constants, 

 Mr. Babbage obsei-ves, that "most of them already exist, and 

 that the difficulty of collecting them consists chiefly in a judi- 

 cious selection of those which deserve the greatest confidence. 

 It would be desirable, however," he adds, " to insert the heads 

 of many columns, although not a single number could be placed 

 in them ; for they would thus point out many an unreaped field 

 within our reach, which requires but the arm of the labourer 

 to gather its produce into the granary of science." Mr. Bab- 

 bage expresses his opinion, that if any scientific body of men 

 would undertake to form such a collection, and to revise it from 

 time to time, it would be a work fraught with advantages to 

 knowledge, by continually leading to the more accurate deter- 

 mination of established facts, and to the discovery and mea- 

 surement of new ones. 



Persons desirous of undertaking or cooperating in the exe~ 

 ecution of any of the foregoing Recommendations, are requested 

 to make known their intention to the Secretaries of the British 

 Association, Musetitn, York. 



