FoN: Dy Ex, 
Night, the caufe of plants evaporating bad air and con- 
taminating common air, p. 47. exp. 36—~5 5.—Danger 
of keeping plants in a room at night, p. 67. 
Night-/bade gives dephlogifticated air by day, exp. 63.— 
Spoils common air by night, exp. 43. 
Nitre, its component parts, p. 118.—What quantity of 
dephlogifticated air it yields, p. 118. 
Nitrous acid yields diiferent kinds of air, p. 117.—Its 
wonderful effe& upon metals, p. 121. 
Nitrous air. What? p. liii—A teft of the goodnefs 
of refpirable airs, p. 97—108.—But fails in fome in- 
flances, p. 99 and feq. exp. 110—115,—This already 
difcovered by Dr. Prieftley, p. li.—how to produce it, 
P- 170.—Its inconftant sa is a great fource of 
"errors in ficulty over- 
come by aie Pontana’s . ether p- 173. re the- 
ory Of this, p. 174.—The beft manner of getting it of 
a conftant quality. p. 170—279.—Why, in the me- 
thod ufed by Dr. Prieftley, the remaining bulk of the 
two airs is greater than in the abridged method fami- 
liar to the author, p. 285. 
Nymphaea Alba, its air-bubbles, p. 16. 
oO. 
_ Oak, its peculiar nature in yielding air bubbles, p. 18. 
—lIts air by night, exp. 37-—lts air in the fhade, exp. 
47.—Its faculty of contaminating common air by 
night, and correGing.it again by day, exp. 50.—Does 
not ‘infest air fo much as fome other trees, exp. 11Ge 
. But fometimes’ much more (perhaps in — 
“ weather), P- 205. 
