PAGE. 
5cean Temperatures 83 
Oil and Vinegar, To Mix D9 
OIe(jmargarine, i-egislation Against 74 
' *Orchestra. Summer's Natural 127 
Ottawa Houses 53 
Out Door World, The 0, 22, 37, 52, 68, 83, 100, 115, 132, 
148,164, 179 
i^Oxygen, Atomic Weight of 87 
^Oxygen (ias, New Method of Preparation 0, 51 
.2(i, 5<i, 87, 121,153, 
Padua, llotanical ( iardens of 
Parasitical Plants 
Paris lyCtter : - 
Pens. Steel 
*Pepper 
periodic I^w 
Pergonal Observations. 1S91. (Prize Essay.) 
Ph'tnicians in Britain. The 12, 
Photochronograph, The 
•Photography in Color 
Photography, Impressionism in 
Photography, Invisible 
Photography by Moonlight 
Photography with Non-actinic Background 153, 
Photography. Novelties in 
Photography, Rapid . - . • 
Pine, Tlie Scotch 
^ Plane, Carpenters", Antiquity of 
* Plan for ( 'leological Study 
plant P.iology, Studies in 2, 33, 64, 1(15, 136, 
Plant, Carnivorous, A 
f*Plants. Devices for Cross Fertilization of 
Tlant Morphology, Comparative 
■Platinum 
Platinum, Advance in Price of 
Platinum, Crystals uf 
Platinum, l^ecrease in Price of 
Pneumonia, Electrical Treatment of 
Pneumonia, Non-alcoholic Treatment of 
Population of the World in 1890 
Potato Culture 
Premonitions, Coincidences, and Superstitions 
Piexcriptions and their Owners '. 
Pressure by Electrolysis ' 
I'ruvention Societies 
•Primrose, Evening 
Princeton Scientific Expedition 
_ problem, A 
^Pumice Stone, f )rigin of 
14fi 
83 
185 
131 
27 
41 
182 
73 
118 
56 
72 
147 
103 
162 
1 
179 
136 
5 
168 
143 
146 
113 
167 
167 
76 
67 
im 
35 
140 
179 
67 
ISl 
INDEX TO \'OLUME XXY 
*Pyramid, The Great, A New Theory of. .... *■ 70 
Pyrogravure 71 
Quarrv, An Ancient 117 
Questions and Answers 12, 29, 43, 58, 74, 94, 106, 123. 
l;«. 155. 170, 187 
Quinine, Artificial 71 
Radicals, Compound 9 
Railroad Construction, Magnificent .*. 5 
Railw ays, Alpine 114 
Rain, Producing by Explosions 119, 151, 167 
Rainbows, Midnight 166 
Raindrop, Work of the - 167 
Roads, Photographs of 41 
*Rock, Balanced, of Tandil 63 
*Ronian Tomb, Contents of 17 
Ropes. To Preserve 51 
Rubber, Effect of Copper on 37 
Rubidium, Great Affinitv for Oxygen of 55 
♦Rubies, Artificial 25 
Rubies, Large 115 
Russian Birds, List of 118 
Russian Insects, List of 118, 134 
Russian Plants, List of 70, 86, 102, 118 
Sands, Musical 135 
Sanguinite, A New Mineral 90 
Saturn, New Markings on 115 
Scallops, Peculiarities of 117 
.Sciences, Definition of 131 
.Scientific Brevities 5,21,36,67,83,1*9, 131, 163, 179 
Scientific Conventions in Washington 151 
•Scientific Recreations 33, 115, 162 
.Scorpions 20 
Sea-Flea, The 69 
Selenium, L'ses of 83 
Shells, Midwinter Trip in Search of 132 
Silicon, New Modification of 41 
Silver, AUotropic Forms of 55 
•Sloths, Giant, of the Past 119, 137 
Smoke Screen 131 
Snow Balls. Natural 41 
Snow on the Moon 151 
Soil, Odor of Moistened 87 
Solution, Nature of 98 
Sparrows Eating Peach Blossoms 180 
Spectroscopy, Solar, Recent Advances in 175 
fACiK. 
Speech in Children, 1 )cvclopineiu of 9 
•Spiders, Aerial 80 
•Spirograph, The 113 
Spring Rock Cave 4 
Squirrels, Carnivorous 13.'l 
Squirrels' Unusual Meal Ilf2 
•Stand, Universal Microscopic 145 
Star of Bethlehem, Tlie 5;t 
Starcli Paper, .Substitute for 82 
Steel Plates, Oil Hardened 114 
Steamboat, An Aluminium .* lOlt 
Stone, Skin for - 114 
•Stonehenge, Astronomical Significance of- 176 
•Submersion Figures 80 
Suez Canal, Widening 131 
Sulphur 178 
Sulphur, AUotropic Forms of 179 
Sulphur, Curious Property of U\i 
Sulphur Spring ^. 101 
Sun. Spectrum of 81 
Sun Spot Phenomena 179 
Teeth, The, In Relation to Health , Ht7 
Telephony, Long Distance ln;i 
Telescopes in the United States H)3 
Temperature, Extraordinary Bodily 41 
Terrestrial Axis, Changes in 37 
Thermometer, An Expensive 21 
Thunder Storms 163 
•Tree, An Extraordinary 128 
Tree, Smallest in (ireat Britain 163 
Tui-pentine, Detecting Adulterations (»f 67 
Vaccination, Proof of \'alue of VMt 
Variation of Organic Forms 18;; 
Varnish, A Good 21 
Waist, Natural Size of i'u 
Water Gas i:i5 
Water (ilobules 54 
Water, Hot, As a Remedial Agent 93 
•Water Plant, A Common 64 
Weather Reports, Local 135, 167 
Welding Metals to Glass 8:j 
Wood, Supply of 167 
Woods that Sink in Water 115 
Woorali Poison 112 
World, End of the I114 
Wortcraft, Saxon 172 
77/^- Publisheys of the PoiTI.AR Scie.nck Xkw.s lo'tU send an extru index sheet, without (id'.ertisin:^ matter, 
to all snhseribers applyini^ for it by postal card or otherwise. 
