Remarks on Objections to Experiments on Vegetation, 215 
crease in purity for twenty days.” And at p. 273, vol. iii. the 
Doctor says: ‘‘ the experiments of this year 1778, to which I had 
been induced to pay more particular attention and care,’ were 
unfavouratle to my former hypothesis.” 1 could adduce more 
experiments of the Doctor’s, of this nature, but think these will 
suffice. 
By whom and by what experiments the doctrine he maintains 
has been “ since ‘confirmed,” I know not, unless the experi- 
ments of Sir Humphry Davy are alluded to. its 
But as Mr. Murray objects to my experiments being con- 
ducted in a confined portion of air, I must remind him that Drs. 
Ingenhousz, Priestley, and Sir H. Davy’s were all performed 
either under water or in a confined portion of air. But perhaps 
he can approve of that in Drs. Priestley, Ingenhousz, and Sir 
H. Davy, which his confirmed opinion will not allow him to do 
with respect to Mr. Tatum. If his object be the support of truth, 
I hope he will not suffer himself to be influenced by partiality, or 
names. { have, it is true, presumed to differ from the above highly ° 
respectable characters ; but I have yet to learn, by what means 
any of these experimenters ascertained the results of vegetation on 
air without its being “ confined ;”” and I hope Mr. Murray will ’ 
have the goodness to inform me, by what peculiar plan he has 
discovered that vegetables pour out such floods of oxygen, an¢ 
he may rest assured I will lose no time in adopting it; and | 
will find me far from being backward to give him all the praise 
Mr. Murray asks, “ If the carbonic gas was at all equiva’ 
to the oxygen se¢ free, whence comes the carbon which beS 
up the plant ?” . l 
I cannot think this question can possibly apply to any!!™8 
related in my paper ; for I there contended that oxygen 19.” 
set free, as such I cannot comprehend the object of the ¢S00- 
He proceeds to say: ‘ the winter no longer contributir the ar 
necessary to life in Europe, the salutary gas is brough!0 us by 
the trade winds from the southern regions.” a 
Really,sir, Mr. M. has drunk deep of Dr. Priestley’?tinciples 5 
for the Doctor entertained unnecessary apprehensieS Of @ de- 
ficiency of oxygen for respiration, and sought for apply, which 
he said he ‘* found in vegetation.”” So Mr. M, Jually appre- 
hensive that the floods poured forth in Europe would not be 
equal to the consumption, imports it from the guthern aioe 
But lkaving heard much talk of the superiorityof the oxygen 0 
the atmosphere at some parts, over that of othis, I was induced 
to ascertain whether such was the case; butas yet I have not 
been able to discover it, and I find I am’ nof solitary in my re- 
sults; for Sir H. Davy could not distinguisi any difference be- 
tween the air brought from Guinea and that of Bristol; and ait 
O04 
