NOTES AND MEMORANDA. REFRIGERATING SALTS.—Herr F. Rudorff has a paper in Poggend. Ann. comparing the refrigerating effect of various salts in solution. The two most remarkable seem to be the sulpho-cyanides of ammonium and potassium ; 133 parts of the former added to 100 of water reduced the temperature of the liquid from 12:2° C. to -18° C., while 150 parts of the latter in 100 of water, reduced it from 10.8° C. to - 23.7° C. or 34:59. To produce a maximum of effect, quantities of from 250 to 500 grammes of the salt employed should be used, in a thin glass vessel surrounded by loose cotton. The salts should be an impalpable powder, and well stirred with the thermometer. A little more of the salt should be used than would suffice to saturate the water. The minimum temperature may be obtained in less than a minute. THE AGE OF WRITINGS IN COMMON INK.-M. F. Carré has communicated to the French Academy remarks on an approximate determination of the age of writing made with ink having like those in common use an iron base. He says, that writing, eight or ten years old may be copied with an ordinary press, if the copying paper is moistened with water to which one-twelfth of hydrochloric acid has been added. In this case the copying is almost as easy, as when it is done upon fresh writing in the usual way. The facility of the copying process diminishes with time, and a writing thirty years old did not give a legible copy, while one dating 1787, scarcely yielded a perceptible trace. When writings are washed with, or soaked in dilute hydrochloric acid of the strength mentioned, an inverse action is noticed. Those made from a few months to ten years ago disappear after an immersion of from a few hours to a few days, while a writing thirty years old could be read after fifteen days maceration. When copies are made with acidulated paper, they should be held over a dish containing liquid ammonia for a few seconds to neutralize the acid. THE COURAGE OF THE WEASEL.-Frequent mention has been made of the boldness of the weasel, which is curiously illustrated by the following fact. The editor was lately walking in his garden in Sussex with two ladies and a gentleman, when a small animal was seen busy on the lawn a few yards off. The party stood still to look at it, and the creature trotted towards them. It made a slight attempt to pass them by dodging behind a bush, but not succeeding, boldly approached, and allowed itself to be taken up in a pocket-handkerchief without a struggle. After being carried about for ten minutes and shown to several people, it was replaced on the grass, but instead of running away, it made a curious squeaking noise, and opened its mouth as if to bite. Stroking it with the handkerchief caused it to renew its bold demonstrations, but on being left alone it ran slowly through an evergreen harbour towards a bank in which it is supposed to live. It did not seem at all afraid, or much annoyed at being handled, and only resented it by diffusing its nasty and characteristic odour. This incident happened in broad daylight. THE APOMECOMETER.—In our April number we gave an account of an ingenious modification of the sextant to form a small pocket instrument for measuring heights, devised by Mr. N. J. Heineken, of Sidmouth. We have since received from that gentle. man a letter stating, that his attention has been called to Millar's apomecometer made by Mr. Stanley, of Great Turnstile, very similar to his own. Mr. Heineken's last instru. ment is only a variation from one he made in December 1868, and was used by him and a friend (Dr. Radford), in January 1869. Mr. Millar and Mr. Heineken, working independently, seem to have devised a very similar modification of the principle of the sextant. INDEX. Arctic expedition from Sweden, 159 440 century, 1 ABNEY Moor, stone circles at, 347 155 BAILEY's beads, 129 working, 70 century, 287 320 rays, 58 stars, 3 Bridlington, turuli near, 60 Concentrating and treating saccharine and saline solutions, 389 Connection between comets and shooting Copal, sources of, 356 Coralline, 228 Corals and their polypes, 81, 241 Cornettes, 202 Correspondence, 71, 156, 460 Costume in the Middle Ages, 196 Cote, 197 Cottus gobio, 455 Coverings for floors, 66 Crater of Vesuvius, 173 Crustacea, Fritz Müller on, 316 Curious page of animal life, 210 Cyprinoids, 410 DAGGER plant, the leaves of the, 26 Damoiselles of the castle, 14 Dartmoor, stone circles at, 347 Darwinism and design, 268 Decoction of worms, 437 Density of hydrogenium, 146, 311 Destruction of ants by poison, 337 Destruction of Pompeii and Herculaneum, 173 Devdoroc, glacier of, 56 240 Dew-worm, 433 Diaphragm for microscope, 429 Digestive system of annelides, 97 Discognathus, 413 Door-mat or scraper, 388 Dorsibranchiata, 93 Dotterill Park, barrow at, 61 Doubtful goby, 71 Dredging report, Dr. Carpenter's, 76 Dress of the burgher class in the Middle Ages, 290 Dress in the Feudal Ages, 19, 194 Durian, the, 223 Dye, poisonous stocking, 229 EARTH, central heat of, 175 Earth, probable appearance of the, from the moon, 252 Earth sbadow, 460 Earth-worms, 432 Eclipse, total solar, 35, 126 Electric lamp, self-regulating, 65 Eliminating nitrogen in working blast fur- paces, etc., 70 444 animals in, 160 195 Gas and vapour, application of, 235 working, 70 sium, 80 ing, 66° Fabrics, textile, 67 137 the, 131 sium, 80 HABITS of Ourang-utan, 223 ing, 66 heavens, 9 131 311 ICEBERGS, size of, 152. Ink, common, age of writings in, 466 Manufacture of gas, 235 Manufacture of gelatine, 388 Manufacturing ammoniacal salts, 391 Manufacturing glass, 386 Mannre, 69 Mare crisium, colour of, 259 Mare serenitatis, colour of, 254 Matches, safety, 69 Material for covering bottles, 387 Mayer, Joseph, statute of, 385 Measuring beights, 236 Medicine, earth-worms as a, 437 Mediæval coins found at Oxford, 314 Meduse, 277 Megascolex, 438 Mercury, notes on a transit of, 157 Metal, paint for protection of, 65 Meteoric observations, 38 Meteorological observations made at Kew, 44, 303 Meteors, April, 220 Meteors, orbits of, determined, 3 Meteors, probable, of Halley's comet, 281 Microscope, diaphragm for, 429 Microscope and the eyesight, 427 Microscopic plants and animals in eruptive rocks, 160 Medieval picnic, 15 Miller's thumb, parental attachment of the, 455 Mimicry of form in insects, 224 Minyadinæ, 87 Mine, Carclaze tin, 154 Minerals, fluid cavities in, 240 Moon, colour in the, 251 Moon, occultations of stars by the, 125, 218, 279, 441 Moon, photographs of the, 156 Multiplication of stentors, 421 Mus marinus, 162 Musical intervals, 239 NAIDES, 432 Natal, insect life in, 336 Nebula, Orion, 186 Nebulæ, classes of, 116 Neckties, fastening for, 391 Needle-case and wrapper, 461 Nephthya chabrolii, 86 Nephthydæ, family of, 263 Nereid, nervous system of, 96 Nereides, family of, 261 Nereids, 161 Nereis tubicola, 169 Nests of the white ant, 337 New direct vision spectroscope, 239 New method of silvering, 69 New rotating stage, 79 |