1ST 
252 
IRR 
«— > An hiftarico-phyfical observation on the waters 
of Neufohl, which are impregnated with 
brafs, and change iron into brafs - Belius 
A letter concerning melting iron with pit-coal 
- Mafo 
— — - An account of a mountain of iron ore at Ta- 
berg in Sweden 
Observations on fand iron 
— A letter on the Solubility of iron in fimple wa- 
ter, by the intervention of fixed air 
— — Account of a fpecimen of native iron Steklin 
— Account of the iron ore lately found in Siberia 
- Pallas 
— — - Experiments on ignited fubflances Whitehurjl 
Irreducible Case. A method of extending Car- 
dan’s rule for refolving one cafe of a cubic 
equation x 3 — - qx ~ r to the other cafe of the 
fame equation, which it is not naturally fitted 
to Solve, and which is therefore called the irre- 
ducible cafe - - Maferes 
Irregularities. Of the irregularities in the pla 
netary motions caufed by the mutual attraction 
of the planets - Walmejly 
Isinglass. An account of the difcovery of the 
manner of making ifinglafs in Ruflia; with a 
particular defbription of its manufacture in 
England, from the produce of Britifh fifheries 
- - - Jack fan 
Island. An account of the funk ifland in the Hum- 
ber, lately recovered from the fea 
Cbamberlane 
• - Part of a letter concerning a new ifland lately 
raifed out of the fea near Tercera ForJl< 
. On the formation of iflands - Dalrymple 
See Santerini. 
Isoperimetrical Problems. An inveftigation o 
a general rule for the refolution of ifoperime 
trical problems of all orders - Siwpfo7i 
— A further attempt to facilitate the refolu- 
tion of ifoperi metrical problems bimpfon 
Isthmus. Letter relating to that ifthmus, or neck o 
land, which is fuppofed to have joined Eng 
land and France in former times, where now is 
the paffage between Dover and Calais Wallis 
IsTRIA. 
Observations in travels from Venice through 
Tranf. 
Abridg. 
XL 351 
VIII 645 
XLIV 370 
X 671 
XL 1 X 30 
LI 1 I 48 
LIX216 
LXIV 461 
LXVI 523 
~ 575 
LXX 85 
LII 273 
LXIII 1 
XXX 1014 
IV 2 251 
XXXII IOO 
LVII 394 
VI 2 203 
XLIX 4 
L 623 
XXII 967 
IV 2 227 
Iftiia, 
