On Chemical Philnf.ophy. 42r> 



taclicd to tlicm, whose office it is to carry them repairs. Now, 

 unless we suppose the series of branching aiteries absolutely in- 

 tinite, it must stop somewhere ; there must be a set of fnie car- 

 riers, that have no carriers to support and repair them. 



The friction, &c. in these fine carrying vessels mav be so small 

 as not materially to injure them in fifty years ; or in one hun- 

 dred years; or in one thousand years; but without repair they 

 cannot last for ever. When the time comes that they are no 

 longer serviceable, the next set above them cease to be fed and 

 repaired When the second set can hold out no longer, the next 

 or third set cease 5 and so on. That is, a gradual decay, he- 

 ginning f I om t lie finest and minutest vessels, is the nccessarij 

 "consequence of tlie repairers in our vascular system not repair- 

 ing themselves. 



It is not necessary for me here to enlarge upon the corre- 

 spondence of the phenomena of old age with the natural results 

 of this principle. I leave that to abler hands ; contented with 

 pointing out, however inadequately and obscurely, a real cause, 

 hitherto unnoticed I believe, of the fatal necessity of animal de- 

 tay. I am, air. 



With great respect yours. 



May 19, 1818. ' Z. A. 



LXXm. On Chemical Philosophy. By Mr, Matvhbw Alla^, 



Lecinrer. 



[Coiitinued from p. 352.] 

 Essay V. 



From the foregoing observations the question naturally again 

 presents itself — " What are the properties of this power by 

 which it is deranged in its distribution, or by which it sufiers 

 pr is capal)le of this derangement in its distribution, and by 

 which again this deranged balance is restored ?" It will be 

 recollected that, in defending the propriety of the generic term, 

 .Attractive Agencies, which was proposed, and under which 

 were classed Electricity, Caloric, and Light, I there considered 

 them as mere phaenomena arising from the active operations 

 uf the power in different states of existence, more or less com- 

 hincd with other substances; and yet characterized thorn as 

 powers still highly attenuated, notwithstanding the idea then 

 t.-irown out, that the diversity of their appearance arose from 

 holding other substances n\ore or less in solution; and that con- 

 sequently (as has been already noticed) it was more or less pure, 

 more or less attenuated or condensed, and more or less rapid in 



its 



