SODA. 



[ 099 ] 



SPECTROSCOPE. 



Meteorolorjie ; Glaisher, Mic. Jn. 1855, iii. ; 

 Kmmann, Mineraloyie. 



SODA. Kolliker recommends a solution 

 of caustic soda, in preference to potash, for 

 the resolution of some of the tissues into 

 their component elements. We have been 

 unable to detect any marked difference be- 

 tween the action of these two solutions ; 

 and the former has the disadvantage of 

 lifting the stopper from the bottle by the 

 crystallization of the carbonate formed; so 

 that it is with difficulty preserved. 



PI. 10. fig. 15 represents the crystals of 

 oxalate of soda; and fig. 19 those of the 

 nitrate (UREA). 



SODIUM, CHLORIDE OF, or common 

 salt. The crystals of this salt belong to 

 the regular system. The most common 

 form is the cube terminated by quadrangu- 

 lar pyramids or quadrangular pyramidal 

 depressions, rectangular tables, &c. Schmidt 

 endeavours to show that the primary form 

 of the crystals is the octahedron, and that 

 the cubes are twin octahedra. The crystals 

 do not polarize light. (Schmidt, Entwurf 

 ein. allg. Untersuch. 90 ; and the Bibl. of 

 CHEMISTRY.) 



SCEMMERING, MIRROR OF. INTRO- 

 DUCTION, p. xxii. 



SOLENOPH'RYA, Cl. & Lach. A 

 genus of Acinetiua. 



Char. Sessile and with a membranous 

 lorica, tentacles simple, in distinct tufts. On 

 roots of Lemna. (Clap, et Lach. Inf. 389.) 



SO'LIUM, Heib. A genus of Biddul- 

 phiese (Diatomacese). (Rabenh. Alg. i. 319.) 



SOLORI'NA, Ach. A genus of Phyl- 

 lodei (Lichenaceous Lichens). 4 species, in 

 mountainous districts. (Leighton, Licli. 

 Fl. 106.) 



SORAS'TRUM, Kiitz. A genus of Des- 

 midiacese. 



Char. Frond globular, composed of com- 

 pressed radiating cuneate cells, bifid at the 

 apex. 



S. spinosum (PI. 3. fig. 22), in stagnant 

 turf-pools. 



BIBL. Kiitzing, Sp. Alg. 195 ; Rabenht. 

 Ah/, iii. 81 ; Carter, Ann. N. H. 1869. 



SORITES, Ehr. See AMPHISORUS and 

 ORBITOLITES. 



SOROSPH^E'RA, Br. A free, Are- 

 naceous Foraminifer, with numerous aub- 

 globular thin-walled chambers (1-5" diam.), 

 loosely attached, and irregularly crowded. 

 S. confusa, in the Atlantic and Pacific, 

 900-2900 fathoms. (Brady, Qu. Mic. Jn. 

 n. s. xix. 9 j 



SOROS 'PORA, Hass. A genus of Pal- 

 mellacece (Confervoid Algae) noc clearly 

 distinguished from Gloeocapsa and Proto- 

 coccus. (Hassall, Alyce, 309.) 



SOROTHE'LIA, Korb. A genus of Mi- 

 crolichens, parasitic on the thallus of Plyc- 

 tis argena. Spores 8, 2-locular, brown. 

 (Lindsay, Qu.M. J. 1869, 343.) 



SO'RUS. The name applied to the ag- 

 gregation of sporanges of the FERNS; some- 

 times applied also to the groups of spores in 

 the Florideous Algas. 



SPATHID'IUM, l\\).=Leucophrysvt. 

 SPATHULA'RIA, P. A genus of Dis- 

 cornycetes (Ascomycetous Fungi), with a 

 fertile head running down the stem on either 

 side. S. flavida is one of our prettiest 

 Fungi when in perfection. 



BIBL. Grev. t. 165; Berk. Outl. t. 21. 

 fig. 7; Cooke, Handb. 661. 



SPECTROSCOPE, OR MICROSPECTRO- 

 SCOPE. The spectrum-analysis of coloured 

 microscopic objects may be effected by 

 means of one or more prisms in connexion 

 with the simple or compound microscope. 

 The prism, or combination of prisms, may 

 be placed, either beneath the achromatic 

 condenser, in the body of the microscope, or 

 in the eyepiece ; and this last arrangement 

 is usually adopted. Sorby and Browning 

 have perfected the microscopic eyepiece. 



Above the eye-glass of the eyepiece, 

 which is made achromatic and capable of 

 focal adjustment for rays of different refran- 

 gibility, is placed a tube containing five 

 1 prisms, two of flint glass interposed between 

 I three of crown glass in such manner that 

 j the emergent rays which have been separa- 

 j ted by the dispersive action of the flint-glass 

 1 prisms are parallel to the rays which enter 

 the combination. Below the eye-glass, in 

 the place of the ordinary stop, is a diaphragm 

 with a narrow slit, which limits the admis- 

 sion of light. Objects placed on the stage 

 of the microscope, provided they transmit a 

 sufficient quantity of light, may then be 

 examined, and their spectra observed. If it 

 is desired to compare their spectra with any 

 other, provision is made for tne formation or* 

 a second spectrum, by the insertion of a 

 right-angled prism which covers one half of 

 the above-mentioned slit and reflects up- 

 j wards the light transmitted through an 

 aperture in the side of the eyepiece. For 

 ! the production of the ordinary spectrum, 

 light is reflected into this aperture from a 

 1 small mirror carried at the side ; while for 

 ' the production of the spectrum of any sub- 



