308 
GENERAL INDEX, 
Optical illusions, S. P. Thompson on some 
new, 1877, 32 
.- illusions of motion; conflicting 
theories referred to the test of certain 
hitherto undescribed entoptical pheno¬ 
mena, Miss B. Lindsay on, 1887, 781 
__instrument which indicates the 
relative changes of position of two 
objects which are maintaining inde¬ 
pendent courses, J. M. Menzies on an, 
1862, 22 
- instruments, various, exhibited by 
M. Hofmann, 1866, 27 
--phenomenon observed on the top of 
Snowdon, A. Schuster on a curious, 
1873, 40 
.-properties of different glasses, Prof. 
Stokes on the researches of the kite 
Rev. W. V. Harcourt on the conditions 
of transparency in glass and the con¬ 
nection between the chemical consti¬ 
tution and, 1871, 38 
—— properties of essential oils, report on 
the chemical constitution and, 1872, 
311 ; 1873, 214 ; 1874, 17 
--properties of a titano-silicic glass, 
Prof. Stokes and J. Hopkinson on the, 
1875, 26 
- theories, report on, by It. T. 
GlazebrooTi , 1885, 157 ; the work of 
MacCullagh, Neumann, Green, and 
Cauchy, ib .; modern developments of 
the elastic solid theory, 170 ; theories 
based on the mutual reaction between 
the ether and matter, 212 ; the electro¬ 
magnetic theory, 251 
-- theories, supplement to a report on, 
by R. T. Glazebrooh, 1887, 208 
Optics, geometrical, Prof. J. C. Maxwell 
on the relation of, to other branches of 
mathematics and physics, 1873, 38 
j--of photography, Antoine Claudet 
on, 1866, 9 
* 0 ptique mineralogique—achromatism e 
des franges, Prof. E. Mascart sur, 1890, 
752 
Optometer, Dr. T. Anderson on a prismatic, 
1881, 521 
Orang (S . satyrus ), Dr. Edwards Crisp 
on the external form of the hand and 
brain of the, 1865, 86 
Orange-peel, Dr. Wright and C. H. Piesse 
on the oxidation products of essential 
oil of, 1871, 83 
Orbits of satellites, Prof. A. Hall on the, 
1886, 542 
-, catenaries, and curved rays, Prof. 
J. D. Everett on the relations between, 
1888, 581 
Orchar (James G.) on the engineering 
manufacture of Dundee, 1867, 144 
Orchids, the occurrence of fungi in the 
roots of, J. Macmillan on, 1885, 1083 
Oreynus alalonga, Dr. W. R. Scott on 
the occurrence of, on the coast of 
Devon, 1865, 93 
*Ord (Dr. W. M.) on the crystallisation 
of salts in colloid solutions, 1872, 79 
* -on crystallisation of urea in pre¬ 
sence of a colloid, 1879, 418 
Ordnance, G. Richards on rifled, 1863, 
182 
-W. D. Gainsford on a newly invented 
system of, 1866, 144 
- Capt. Wynant on barytic powder 
for heavy, 1866, 148 
-- Department, a communication from 
the, on surveys in Ireland, 1874, 184 
-datum of Great Britain, a more 
extended use of the, J. N. Shoolbred 
on, 1877, 218 
- Survey of Great Britain, report on 
the datum level of the, with a view to 
its establishment on a surer foundation 
than hitherto, and to tabulate and com¬ 
pare other datum-marks, 1877, 220 : 
1878, 219 ; 1879, 219 
* - Survey, photographic and photo- 
zincographic processes employed in 
the, Col. J. H. Bolland on, 1888, 746 
-Survey, the, some defects of, S. H. 
Wilkinson on, 1887, 804 
* -Survey, the utilisation of the, Col. 
Sir C. Wilson on, 1887, 804 
f-- Survey, the present state of the, 
and the paramount necessity for a 
thorough revision, H. T. Crook on. 
1890, 896 
*—-—- Survey of Cyprus, T. Saunders on 
the, 1885, 1129 
Ordovician rocks of Shropshire, Prof. C. 
Lapworth on the, 1886, 661 
O’Reilly (Prof. J. P.) on the correlation 
of lines of direction on the globe, and 
particularly of coast lines, 1878, 547 
-on the relation to be established 
between coast-line directions repre¬ 
sented by great circles on the globe 
and the localities marked by earth¬ 
quakes in Europe, 1880, 576 
Organic acids, report of synthetical re¬ 
searches on, by Alfred R. Cation, 1868, 
475 
-acids, the application of, to the 
examination of minerals, Prof. H. C. 
Bolton on, 1880, 505 
* - analysis by a moist process, a 
method of elementary, Prof. Wanklyn 
and W. J. Cooper on, 1878, 517 
-- compounds, Dr. Odling on the 
nomenclature of, 1862, 48 
-compounds, a plea for the empiric 
naming of, by Prof. Odling, 1885, 972 
- compounds, Dr. Phipson on a new 
class of, 1862, 50 
-functions, Dr. Richardson on effects 
of extreme cold on, 1868, 119 
- remains of the North Staffordshire 
