from fatigue belonging to the use of this form of miscroscope; for when placed on a table, rather higher than the one commonly used, and a foot or two from the edge, the observer can recline on his arms, and observe for hours without the slightest sensation of fatigue. Messrs. J. & W. Grunow, New Haven, Conn.,

are the manufacturers of this instrument.

DR. J. LAWRENCE SMITH'S GONIOMETER AND MICROMETER.

Professor Smith has also invented a Goniometer for measuring the angles of crystals under the microscope. It is also combined with a Micrometer. The following is a description of the instrument with the method of using. (Figs. 433-4.)

E is the upper end of the draw-tube of the microscope, with the ring k soldered to it. Over this ring k, screws another ring F, which serves as a support and as a centre to the graduated circle D, which freely, but without shaking, revolves upon the same. Into the bore of the ring F, fits by its lower conical end h, the tube G, which is held in it by a screw-ring y, that prevents its being taken out. Into the tube G, which also has a free revolving movement, fits the positive eye-piece a, d being the field-lens, 8 the eye-lens.

The slide bb, on opposite sides of G, admits of the micrometer with its mounting B, B being introduced into G, and the graduation being brought into the field of the eye-piece.

C is an index, attached to G by the screw c; it may be taken off, when the apparatus is not used as a goniometer.

1 See American Journal of Science and Arts, for September, 1852, in which the entire paper of Prof. Smith will be found.

USE OF THE GONIOMETER.

Bring the object into focus near the centre of the field of the micrometer, apply your finger to the knob K, and revolve the micrometer, till the lines of its graduation are parallel to one

side of the angle to be measured. Revolve then separately the graduated circle, till zero is brought to agree with the point of the index C. Then revolve again the micrometer by the knob K, until the graduation lines are parallel to the other side of the angle to be measured, when the index C will show the value of this angle. (The references are the same in both cuts.) The graduated lines of the micrometer are generally of the American inch apart. But their relative value as micrometer, with the different object-glasses and eye-pieces, must be ascertained by a glass stage-micrometer, and recorded in a table.

INDEX..

Aberration, chromatic, 73, 74.
spherical, 71, 72.

Acalephs, see Medusa.

Acarida, 581, 582.

Achyla prolifera, 315, 316.

Acineta-form of Vorticella, 419, 420.
Achnanthes, 297.

Achromatic Condenser, 131-133, 136; use
of, 172, 173.

Achromatic correction, 41; principle of, 73,
74; application of, 74-76.
Actiniform Zoophytes, 474-476.
Actinocyclus, 289, 290.

Actinophrys, 407-409.

Adipose tissue, 607, 608, 664.

Adjustment of Focus, 86, 87; uses of, 162-

165.

of Object-glass, for thickness
of cover, 76, 77; mode of
making, 165-168.

Agates, sponge-remains in, 633.

Apple, cuticle of, 389, 390.
Anthozoa, 457, 472-476.
Apus, 544.

Aquatic Box, 148, 169.

ARACHNIDA, microscopic forms of, 581, 582;
eyes of, 582; respiratory organs of, 582,
583; feet of, 583; spinning apparatus of,
583.

Archegonia, of Marchantia, 344-347; of
Mosses, 349; of Ferns, 356-358.

Arachnoidiscus, 290, 291.

Arcus Senilis, 665.
Areolar tissue, 603.
Argulus, 547, 548.
Artemia, 545.

Air-bubbles, microscopic appearances of, Ascaris, 531, 532.

184.

Alcyonian Zoophytes, 472–474.
Alcyonidium, 496, 497.

Asci of Lichens, 334; of Fungi, 335.
Ascidians, compound, 50, 500; social, 502-

505.

ALGE, higher, microscopic structure of, Asphalte, use of, 207.
328-333 (see Protophyta).
Amaroucium, structure of, 501, 502.
Amici's Prism for oblique illumination, 137.
Amaba, 405-407.

Anacharis alsinastrum, rotation in, 364,
365.

Anagallis, petal of, spiral vessels in, 396.
Angular aperture of object-glasses, 71-73,
76; real value of, 188-192.
Animalcule-Cage, 148, 168.
ANIMALCULES, early researches on, 38;
Ehrenberg's observations on, 47-49, 411-
421; Dujardin's researches on, 49; see
Infusoria, Rhizopoda, and Rotifera.
Animals, Distinction of, from Plants, 247,
248, 409, 410.

ANNELIDA, 535; marine, circulation in, 535,
536; metamorphoses of, 536, 537; lumi-
nosity of, 537; fresh-water, 537, 538.
Annular Condenser, Shadbolt's, 139, 140.
ANNULOSA, 529; see Entozoa, Turbellaria,
and Annelida.

Anomia, structure of shell of, 512.
Antennæ of Insects, 564, 565.
Anthers, structure of, 396, 397.
Antheridia of Cryptogamia, discovery of,
45, 46; see Antherozoids.

Antherozoids, of Vaucheria, 314; of Sphæ-

Asteriada, skeleton of, 482, 483; metamor-
Aspidium, fructification of, 353-355.
Aspidisca-form of Trichoda, 421.
Asteroida, 472-474.
phoses of, 486-488.

Avicularia of Polyzoa, 498, 499.
Auditory vesicles of Mollusks, 527, 528;
development of, 525.

Azure blue butterfly, scales of, 195, 558.

Bacillaria paradoxa, 296; movements of,
Bailey, Prof., his diatomaceous tests, 199.
287, 288.
Bark, structure of, 384, 385.
Balani, metamorphoses of, 548-550.
Bat, hair of, 195, 595, 596.
Battledoor scale of Polyommatus, 195, 558.
Barnacles, metamorphoses of, 548–550.
Batrachospermeæ, 321, 322.

Bee, eyes of, 561; proboscis of, 567;
wings of, 574; sting of, 578.
Berg-mehl, 303, 304.
Beroe, 470, 471.

Binocular Microscopes, 114-117.
Biddulphia, 299; markings on, 281; self-
division of, 284.

Bird, Dr. Golding, on preparation of Zoo-
phytes, 474.

BIRDS, bone of, 587; feathers of, 597, 598;
blood of, 599, 600; lungs of, 624-626.
Bird's-head processes of Polyzoa, 498, 499.
Black-Japan varnish, 219.
Black-Ground Illuminators, 138-140, 174,
175.

Blenny, viviparous, scales of, 591.
Blood Disks of Vertebrata, 183, 598-601;
mode of examining and preserving, 601,
602; circulation of, mode of examining,
616-619, 691.

Blood vessels, injected preparations of,
619-623; disposition of, in different parts,
623-626; morbid, 666.

Bone, structure of, 183, 584-587; mode of
making sections of, 207-211, 587.
Bones, Fossil, examination of, 207-643.
Botrytis bassiana, 336.

Botryllians, 502.

Bowerbankia, 50, 496, 500.

Brachionus, 427, 429, 434.

324; multiplication of, by zoospores, 324;
sexual apparatus of, 325, 326.
Cherry-stone, cells of, 368.
Chemical Reagents, use of, in Microscopic
research, 211-213.

Chilodon, teeth of, 415; self-division of,
418.

Chirodota, calcareous skeleton of, 486.
Chloride of Calcium, as mounting mediam.

233.

Choroid, pigment of, 605.

Chromatic Aberration, 71, 72; means of re
ducing and correcting, 73, 74.
Chromatophores of Cephalopods, 527.
Cidaris, spines of, 481.

Ciliary action, nature of, 424, 425; on gills
of Mollusks, 527.

Ciliated epithelium, 606, 607.

Circulation of Blood in Vertebrata, 616-
619; in Insects, 569, 570; alternating, ia
Tunicata, 504, 505.

Brachiopoda, structure of shell of, 513-515. Cirrhipeds, metamorphoses of, 548-530.

Branchiopoda, 542-545.

Branchipus, 545.

Brooke, Mr., his Object-glass holder, 127.
Brunswick-black, use of, 218.

Buccinum, tongue of, 521; egg-capsules
of, 522; development of, 523.
Bugs and their allies, 648; wings of, 676.
Bugula avicularia, 498. 499.

Bull's-Eye Condenser, 143; use of, 178.
Busk, Mr. G., on Volvox, 260, 265.
Butterflies, see Lepidoptera.

Cabinets for microscopic objects, 243.

Cactus, raphides of, 371.

Calycanthus, stem of, 385.

Clavellinida, 503.

Clarke, Mr. J. L., his mode of preparing
sections of Spinal Cord, 616.

Cleanliness, importance of, to Microscope,

158-160; in mounting objects, 242.
Closterium, movement of fluid in, 267, 268;
duplicative subdivision of, 268, 269; mul-
tiplication of, by gonidia, 275; conjuga-
tion of, 274.

Clypeaster, spines of, 481.
Coal, nature of, 627-629.
Coarse-adjustment, 86-88; uses of, 162, 163.
Cockchaffer, cellular integument of, 556;
eyes of, 562; antenna of, 565; spiracle of
larva of, 572.

Cockle of wheat, 531, 532.

Camera Lucida, 125, 126; use of, in Mi- Coddington lens 80.
crometry, 126.
Campanularida, 463–465.
Campylodiscus, 292.

Canada balsam, use of, as cement, 208, 209,
219, 220; mounting of objects in, 224-232.
Canal-system of Foraminifera, 446, 447.
Canaliculi of bone, 585-587.
Cancer cells, 675.

Capillaries, circulation in, 616-619; injec-
tion of, 619-622; distribution of, 623-626.
Carp, scales of, 592.

Cartilage, structure of, 608, 609.
Cells for mounting objects, of cement, 235;
of thin glass, 236; of plate-glass, 237;
shallow, 237; deep and built up, 238-240;
mounting objects in, 240-242.
Cells, Animal, nature of, 404, 405.
Cells, Vegetable, 42; nature of, 249;
rotation in, 363-367; thickening deposits
in, 367, 368; spiral deposits in, 369;
starch-grains in, 370 371; raphides in, 371.
Cellular Tissue, ordinary form of, 360-362;
stellate, 362; cubical, 363; dimensions
of, 363; component cells of, 363.
Cement-Cells, mode of making, 235, 236.
Cementum of Teeth, 589-591.
CEPHALOPODS, shell of, 516, 517; chromato-
phores of, 528.
Ceramiacea, 331.
Chatophoracea, 321, 322.

Chalk, Foraminifera, &c., of, 631-633.
Characea, 322, 323; rotation of fluid in, 47, ❘

Cohn, Dr., his account of various states of
Protococcus, 253-259; his researches on
Infusoria, 425, note; on reproduction of
Rotifera, 430, 431.

Coleoptera, mouth of, 565-567.
Collection of objects, general directions for,
243-245.

Collomia, spiral fibres of, 368–370.
Colostrum, 683.

Columella of Mosses, 351.
Comatula, metamorphosis of, 490.
Compound Microscope, principle of, 81-85;
various forms of, 96-117.
Compressorium, 150-152; use of, 168.
Concave lenses, refraction by, 69,
Conceptacles of Marchantia, 345, 346.
Condenser, Achromatic, 131-133, 136; use
of, 172, 173.
Annular, 139.

for Opaque Objects. ordinary,
144; bull's-eye, 144; mode
of using, 177-179.

Confervaceæ, 317; self-division of, 318;
zoospores of, 318; sexual reproduction of,
318, 319.

Conifera, peculiar woody fibre of, 372; ab.
sence of ducts in, 375, 382; fossil, 382,
628,629.

Conjugation of Palmoglæa, 252; of Des-
midiaceæ, 274-276; of Diatomaceæ, 284-
286; of Conjugateæ, 319, 320; (supposed)
of Actinophrys, 408.