1 54 -fin Ejffeiy on Longevity. 



The fame chemifts, to prove their afTertion, date, that 

 copper does not decompofe the carbonic: acid, as iron does in 

 the experiment of Cruickfhank. But it may be laid in an- 

 fvver, that as the former metal does not decompofe the water, 

 it may not have the property of decompofing carbonic acid. 



In a word, the combination of inflammable gas with ful- 

 phur, obtained by the Dutch chemifts, and which they took 

 to be fulphurated hydrogen, was only a mixture of that gas 

 with the gafeous oxide of carbon a little fulphurated, of which 

 we have already fpoken. 



Carburated fulphur is not a difcovery entirely new : finee 

 our labour we have learned that it had been announced in 

 fome work or other before. 



XXVIII. An EJfay on Longevity. By Sir John 

 Sinclair, Bart. 



— «-^ Introduction. 



1 HE means of preserving health, and of attaining great 

 age, are fubje&s which feem to be well entitled to the pecu- 

 liar attention of every thinking man. In regard to the for- 

 mer, there is no queftion : the pleafure that arifes from the 

 poffeflion of health, and the diftrefs which ficknefs occafions, 

 are perpetual mementos that health cannot be neglected. 

 But as to the latter, the propriety of afpiring to long life has 

 been doubted ; and it is faid, after a perfon has lived for 

 50 or 60 years, and has fulfilled his duties as a man, that he 

 had better retire to make way for others, and that the fooncf 

 he quits thefe fublunary fcenes the better. Such fentiments, 

 however, ought not to be indulged. If perfons lived only for 

 themfelves, and for the gratification of their own paffions, 

 and to promote their own interefts alone, this might be the 

 cafe. But if we live, as we ought to do, to promote the hap- 

 pinefs of others as well as our own, and if by living long 

 we can be of more fervice, from the knowledge which greater 

 experience and longer obfervation muft neceflarily furnifli, 

 the refult is, that we ought to live as long as we have, health 

 and ftrength to perform good actions to others, and that the 

 power of doing good ought to be the proper limit by which 

 our wi flies for exiftence ought to be bounded : nor ought it 

 to be omitted, that there is an evident and neceffary connec- 

 tion between good health and longevity, as it is impofiible 

 to pofTefs the one without its contributing to the enjoyment of 

 tfie other. 



In fketching out fome obfervations on this important fub- 



