Page:Encyclopædia Britannica, Ninth Edition, v. 18.djvu/878

 842 O P H R these data and a very simple calculation it followed that the light of the sun was about 256,289 times that of the moon. Other experiments followed, and the average of all the results was that the light of the sun was about 300,000 times the average light of a full moon, both being viewed in the heavens at the same altitudes. The details will be found in Bouguer s Traite d Optique. Wollaston in 1829 tried a series of experiments in which the ratio 801,072 was obtained ; but the omission of certain necessary pre cautions vitiates the result (Phil. Tram., 1829). Bond (Mem. Amer. Acad., 1851, p. 295) adopted a different process. He formed the image of the sun on a silvered globe of some 10 inches diameter; the light of this image was reflected on to a small mercurial thermometer bulb ; and then this second image was compared with a Bengal light so moved that the lights appeared to be equal. The same process was adopted with the full moon instead of with the sun. The result was that the sun s light was 470,980 times that of the moon. Seidel long before this date had compared the light of the mean full moon with that of Jupiter in mean opposition ; his result is 6430. So also this light of Jupiter was found to be &quot;4864 times that of Venus at her brightest ; and Jupiter was found to give 8 2 times the light of a Lyroe. If, then, these numbers could be accepted with confidence, we should have the means of comparing the light received from the sun with that received from any of the stars. Adopting these pre carious numbers on the authorities of Bond and Seidel we have the following results- Sun s light = 470,980 that of the full moon. ,, = 622,600,000 ,, Venus at her brightest. ,, = 302,835,000 ,, Jupiter at mean opposition. ,, =5,970,500,000 ,, Sinus. Lastly, Bouguer, by comparing the light of the full moon viewed at different altitudes with an artificial light, found that the atmosphere absorbs 1877 of the light incident on it at the zenith of any place. Professor Pritchard, from photometric, measures taken at Cairo, found this number to be -157. At Oxford it was &quot;209. Thus Bouguer s determination indicates an absorptive capacity in the atmosphere of Brittany just midway between those of Oxford and Cairo. Seidel at Munich expresses &quot;sur prise &quot; at finding his own results so nearly accordant with Bouguer s. These numbers, therefore, may be regarded as close approximations to fact. 1 (c. p.) PHOTOPHONE. See TELEPHONE. PHRENOLOGY. This name was given by Forster in 1815 to the empirical system of psychology formulated by Gall and developed by his followers, especially by Spurz- heim and Combe. At first it was named &quot; cranioscopy,&quot; &quot;craniology,&quot; &quot;physiognomy,&quot; or &quot;zoonomy,&quot; but Forster s name was early adopted by Spurzheim, and became that whereby the system is now known. The principles upon which it is based are four : (1) the brain is the organ of the mind ; (2) the mental powers of man can be analysed into a definite number of independent faculties ; (3) these faculties are innate, and each has its seat in a definite region of the brain ; (4) the size of each of these regions is the measure of the power of manifesting the faculty associated with it. While phrenology is thus, on the one hand, a system of mental philosophy, it has a second and more popular aspect as a method whereby the disposition and character of the individual may be ascertained. These two sides of the subject are distinct from each other, for, - Since this article was put in type, Professor Pickering at Harvard College has published his concluded results. Professor Pritchard at Oxford has also completed his photometric measures of some 2000 of the same stars. Taken as a whole, and as comprising the first com plete and systematic efforts in a new and difficult line of research, the agreements of the two catalogues may fairly be regarded as very satis factory, not to say surprising. while it can only serve as a reliable guide for reading character on the assumption of its truth as a philosophic system, yet the possibility of its practical application does not necessarily follow from the establishment of the truth of its theoretic side. History. That the phenomena of mind are in some measure connected with the action of the brain has been recognized from a very early age of philosophy. It is true that Aristotle 2 describes the brain as the coldest and most bloodless of bodily organs, of the nature of water and earth, whose chief purpose is to temper the excessive heat of the heart, as the cooler regions of the firmament condense the vapours rising from the earth. In his view, as in that of most of the earlier writers of other nations of antiquity, the heart is the seat of life ; to it, not to the brain, the Hebrew writers refer thoughts and affections, while they considered judgment as seated sometimes in the head, sometimes in the kidneys. 8 This was, likewise, the teach ing of the ancient Egyptian philosophy ; and hence, while many rites were practised and many prayers offered for the preservation of the heart of the deceased, the brains were passed over with very little precaution for their pre servation. 4 The influence of the Aristotelian teaching is traceable in that of some of the earlier classic writings on philosophy, as is that of the Hebrews in our own collo quial language ; but we learn from Diogenes Laertius 5 that much more accurate physiological views were held by Pythagoras, who believed the mind and the intellect to have their seat in the brain. The theory of Hippocrates was Pythagorean rather than Aristotelian, for, although in one passage in his work De Corde he expresses himself rather doubtfully, yet elsewhere he clearly states that he considers the brain to be the index and messenger of the intellect. 6 The cerebral seat of sense -perception is also taught by Plato, 7 who puts into the mouth of Socrates the theory that the brain is the organ affected by the senses, whereby memory and opinion arise, and from whence know ledge springs. The classic poets also notice this depend ence of mind on brain; for example, in the Clouds (v. 1276) Strepsiades accuses Amynias of not being in his right mind, and, on being asked why, responds, &quot; You seem to me as if you had had a concussion of the brain.&quot; The two founders of anatomical science, Erasistratus and Herophilus, who lived in the days of Ptolemy Soter, taught not only that the brain was the seat of sensation and of intellect, but also that there was therein a certain degree of localization of function. Erasistratus believed that the sensory nerves arose from the brain-membranes, the motor from the cerebral substance. Herophilus was apparently the first who held that the vital forces resided in and circulated from the ventricles of the brain, at least so we gather from Celsus and the other authors who have preserved his views. By the influence of the writings of Galen, 8 which directly teach that the brain is the seat of 2 De partihus animalium, ii. c. 7 (Paris, 1629, p. 986). 3 In the Chaldee portion of Daniel (ii. 28, iv. 5, vii. 1) visions and thoughts are referred to the head. For other particulars as to early views see Nasse on the psychical relations of the heart in Xe.itsrlir. f. psychische Aerzte, i., 1818. A few of the later medical writers express similar views ; see Santa Cruz, Opuscula medica, Madrid, 1624. 4 nook of the Dead, ch. xxvi. -xxx. 8 viii. 30, ed. Cobet, Paris, 1850, p. 211, &quot;3&amp;gt;ptvas 5e Kal vovv, TO. tv T&amp;lt;$ fyK^(f&amp;gt;atf}.&quot; 6 &quot;Demorbo sacro,&quot;in Opp., ed. Kiihn, i. 612 .iq. ; also Epist., iii. 824. Among later writers Licetus of Genoa taught the coextension of soul and body, upon which subject he wrote two books (Padua, 1616). In this connexion may be noted a curious work by Schegkius, Dia- logus de animae principatu, Aristotelis et Galeni rationes prseferens quibus ille cordi, hie cerebro, principatum attribuit, Tubingen, 1542. 7 Pheedo, ch. xlv., Valpy s ed., 1833, p. 128. See also Haller s Bibl. anat., i. 30. 8 De usu partium, ed. Kiihn, iii. 700, &quot;ras ^v o7&amp;gt;v airoSel^eis TOV rr)v oyiffTiKrjv otcev fv