618 
INDEX. 
Photographic action, on a definite limit of, of the blue rays under the influence of an iodic salt, 52. 
image. On a new method of producing it with greater distinctness, 325. 
papers, 327 ; method of using, 332. 
processes, on some, 1. I. Of fixing photographs, 4; II. Of taking photographic 
copies and transfers, 7 ; III. Of the preparation of photographic paper, 8. 
Photometer , self-registering, for meteorological purposes, 46. 
Pillars of cast iron and other materials, experimental researches on the strength of, 385 ; compara- 
tive strength of cylindrical pillars of cast iron, with rounded and with flat ends, 387 ; strength 
of long pillars of cast iron, 390 ; of pillars with one end rounded and the other flat, 393 ; of 
pillars enlarged in the middle, 395; of long pillars as dependent upon their dimensions, ibid. ; 
upon the diameter, ibid. ; on the length, 398 ; computations of the strength of long 
pillars by means of the numerical results from experiments, 400; short pillars, diminution in 
their strength from crushing, 403 ; mode of estimating the strength in short pillars, 404; rela- 
tive strength of similar pillars, 400; strength of hollow cylindrical pillars of cast iron, 408; 
computed strength, 414; strength of short hollow pillars, 416; power of cast iron to resist 
long-continued pressure, 417 ; tensile strength of cast iron, 418 ; compressive strength of cast 
iron, 419; transverse strength of cast iron, 420; strength of pillars of wrought iron, of steel, 
and of timber, ibid. ; strength of pillars of wrought iron as dependent on their dimensions, 
423 ; — of timber, 424 ; — crushing strength of timber, 429 ; relative strength of long pillars of 
cast iron, wrought iron, steel, and timber, 430 ; Tables : I. Results of experiments on the re- 
sistance of solid uniform cylinders of cast iron to a crushing force, the ends rounded, 431 ; 
II. Ends of the cylinders turned flat, 434 ; III. Rectangular or square uniform pillars, 437 ; 
IV. Solid uniform cylindrical pillars with discs upon their ends, 438 ; V. Uniform pillars, with 
one end rounded and one flat ; with both ends rounded ; with both flat, 439 ; VI. Pil- 
liars enlarged in the middle, ends rounded, 440; VII. Pillars enlarged in the middle, with 
discs on the ends, 441 ; VIII. Hollow cylinders rounded at the ends, 442 ; IX. Hollow cylin- 
ders flat at the ends, 445 ; X. Short hollow cylinders, 448 ; XI. Pillars of various forms and 
different modes of placing, 449 ; XII. Pillars of wrought iron and steel, 451 ; XIII. Pillars 
of Dantzic oak and red deal, 453. 
Powell (the Rev. Baden). A supplement to a paper entitled “ Remarks on the Theory of the 
Dispersion of Light as connected with Polarization,” 157. 
Precession and nutation, phenomena of, assuming the interior of the earth to be fluid and hetero- 
geneous, 193. 
Prismatic colour, a new, 19. 
spectrum, extension of the visible, 19. 
R. 
Rabbit, ova found in the Fallopian tube and uterus of the, 565 ; table of measurements of ova, 567. 
Rays of the solar spectrum \, on the chemical action of the, on preparations of silver and other 
substances, both metallic and non-metallic, 1 ; combined chemical action of rays of different 
degrees of refrangibility, 23 ; of the whitening process of the several, under the influence of 
the hydriodic salts, on papers variously prepared and previously darkened by the action of 
solar light, 35 ; analysis of the chemical, by absorbent media, 37. 
Redrays, chemical action traced much beyond the extreme, 28, 31 ; exercise of a deoxidating 
power by the, 28. 
Resins, on the constitution of the. Part IV., 341 ; IX. Resin of scammony, ibid. ; X. Resin 
