| Partial eclipse of the moon | Initial letter | 1 |
| A boy illustrating the phases of the moon | | 6 |
| Course of the moon in the heavens | | 8 |
| Chart of the moon | | 10 |
| Face of the full moon | | 11 |
| Tycho and his surroundings | (from a photograph by De la Rue) | 13 |
| Plan of the peak of Teneriffe | | 15 |
| The crater Copernicus | | 17 |
| The lunar Appennines | (from a photograph by M.M. Henri) | 19 |
| The crater Plato seen soon after sunrise | | 20 |
| Diagram of total eclipse of the moon | | 23 |
| Boy and microscope | Initial letter | 27 |
| Eye-ball seen from the front | | 30 |
| Section of an eye looking at a pencil | | 31 |
| Image of a candle-flame thrown on paper by a lens | | 33 |
| Arrow magnified by a convex lens | | 35 |
| Student's microscope | | 36 |
| Skeleton of a microscope | | 37 |
| Fossil diatoms seen under the microscope | | 39 |
| An astronomical telescope | | 41 |
| Two skeletons of telescopes | | 44 |
| The photographic camera | | 47 |
| Kirchhoff's spectroscope | | 51 |
| Passage of rays through the spectroscope | | 52 |
| A group of fairy-ring mushrooms | Initial letter | 55 |
| Three forms of vegetable mould magnified | | 61 |
| Mucor Mucedo greatly magnified | | 63 |
| Yeast cells growing under the microscope | | 65 |
| Early stages of the mushroom | | 67 |
| Later stages of the mushroom | | 68 |
| Microscopic structure of mushroom gills | | 69 |
| A group of cup lichens | Initial letter | 75 |
| Examples of lichens from life | | 77 |
| Singe-celled plants growing | | 78 |
| Sections of lichens | | 81 |
| Fructification of a lichen | | 83 |
| A stem of feathery moss from life | | 85 |
| Moss-leaf magnified | | 87 |
| Polytrichum Commune, a large hair-moss | | 88 |
| Fructification of a moss | | 89 |
| Sphagnum moss from a Devonshire bog | | 93 |
| Surface of a lava-flow | Initial letter | 96 |
| Vesuvius as seen in eruption | | 97 |
| Top of Vesuvius in 1864 | | 100 |
| Diagrammatic section of an active volcano | | 105 |
| Section of a lava-flow | | 108 |
| Volcanic glass with crystallites and microliths | | 109 |
| Volcanic glass with well-developed microliths | | 110 |
| A piece of Dartmoor granite | | 112 |
| Volcanic glass showing large included crystals | | 115 |
| A total eclipse of the sun | Initial letter | 117 |
| Face of the sun projected on a piece of cardboard | | 120 |
| Photograph of the sun's face, taken by Mr. Selwyn | (Secchi, Le Soleil) | 122 |
| Total eclipse of the sun, showing corona and prominences | (Guillemin, Le Ciel) | 124 |
| Kirchhoff's experiment on the dark sodium line | | 128 |
| The spectroscope attached to the telescope for solar work | | 132 |
| Sun-spectrum and prominence spectrum compared | | 134 |
| Red prominences, as drawn by Mr. Lockyer 1869 | | 136 |
| A quiet sun-spot | | 140 |
| A tumultuous sun-spot | | 141 |
| A star-cluster | Initial letter | 145 |
| Some constellations seen on looking south in March from six to nine o'clock | | 148 |
| The chief stars of Orion, with Aldebaran | | 149 |
| The trapezium θ Orionis | | 150 |
| Spectrum of Orion's nebula and sun-spectrum compared | | 151 |
| Some constellations seen on looking north in March from six to nine o'clock | | 156 |
| The Great Bear, showing position of the binary star | | 157 |
| Drifting of the seven stars of Charles's Wain | | 159 |
| Cassiopeia and the heavenly bodies near | | 162 |
| ε Lyræ, a double-binary star | | 166 |
| A seaside pool | Initial letter | 172 |
| A group of seaweeds (natural size) | | 175 |
| ULVA LACTUCA, a piece greatly magnified | | 176 |
| Seaweeds, magnified to show fruits | | 177 |
| A Coralline and Sertularian compared | | 179 |
| Sertularia Tenella hanging in water | | 180 |
| Thuricolla Folliculata and Chilomonas Amygdalum | | 182 |
| A group of living diatoms | | 184 |
| A diatom growing | | 185 |
| Cydippe Pileus, animal and structure | | 187 |
| The Sea-mat, Flustra Foliacea | | 191 |
| Diagram of the Flustra animal | | 192 |
| Dartmoor ponies | Initial letter | 195 |
| Equus Hemionus, the horse-ass of Tartary and Tibet | | 201 |
| Przevalsky's wild horse | | 202 |
| skeleton of an animal of the horse-tribe | | 206 |
| Palæolithic man chipping flint tools | Initial letter | 209 |
| Scene in Palæolithic times | | 212 |
| Palæolithic relics—needle, tooth, implement | | 213 |
| Mammoth engraved on ivory | | 216 |
| Neolithic implements—hatchet, celt, spindle whorl | | 219 |
| A burial in Neolithic times | | 221 |
| British relics—coin, bronze celt, and bracelet | | 223 |
| Britons taking refuge in the cave | | 224 |
