12 
REPORT— 1854. 
nifying power. Dr. Diamond, who printed the positive of the moon, found the m.-, 
picture, however, rather overdone for transferring. — It will be necessary, therefurr, 
either to use collodion and nitrate of silver simply, without any or but little senH- 
tive solution, or else to pass the sun's rays through some coloured glass, which w II 
partially retard their energy. A series of pictures of the spots on the sun, sni; 
as of the general surface, may then be successfully obtained; and hence il is not to" 
much to anticipate some accession to our knowledge of the physical character of 
both our great luminaries by means of this gigantic telescope, which Dr. Diamond 
enables me to exhibit photographically to the Section. 
Oil Errors which may be occasioned by disregarding the Influence of Sola 
or Artificial Light on Magnets. By Sir John ltoss. 
On the Deviation of the Magnetic Needle peculiar to Liverpool 
By Sir John Hobs. 
rhe author stated that his attentiun has for some time been caljed to tbr fact^ 
ships sailing from the port of Liverpool, after having been swung in the Mov. 
obtain the amount of deviations, that immediately on their proceeding ou 
voyage it was found that the deviation observed in' the Mersey was meorreo, am. 
there have been lamentable instances of shipwreck attributed to this cau-' 1 
occurred to him that this untoward circumstance is very easily explained. 
Mersey is not a locality eligible for ascertaining the true deviation of the n»P ‘ 
needle, the ships being in a position between establishments in which large 
of iron are deposited, which must have an influence on the magnetic needle M 
* v w o11011011 of swinging the ship, while the embarkation of passengers w-u^ 
° ra ^ 1 t llD g c,se subsequent to that process, cannot but huve 
a ^ a [ ac and dangerous result to the observations. r Io o.- rac ) v 
l tioTed S n th , at th0 P r ent of swinging the ship in the \ *l 
ill t! ’ and '. m 0r ^ cl ' to obtain a verification or a correction of result ^ 
hmfJ f ' 18 P ro P° s, - (I to place oft the sandhills of Rockland (neur the Koc , - , 
PKt 2’ o tW0 P °l ts or btuc( »ns, true nort h and south of each other, in tb* I* 
steerin i near tk ‘ red buo >' of the Rock Channel, when the pa f J u0 ^ 
can llp S h abou ‘ tn "-‘ west ' or west-north-west, by compass. W hen thf» f ,.. : 
a verifirm-° U6k r 11 i 0One ' f,ue norf h ofdU?h (both being south of b jlin : 
differ^ t 0 * n ,hp deviafi on that was observed in the Mersey, or the 
the com. 6 t0 b n , talien int0 considers tlutl or account on that P tt V 1 - 
of thSofw’ W l ljesh0Wn ' fVom which a calculation may be 
Sa rr iand if ' Arthur on, two other posts were erected^ #v r 
the exact' ^ 0,1 passing them, when in one with each other, u 
variadon on .1 U “ t0f ** dw ®°“ eilher in thc incrcftse ° r ton the 
DoCTt of t^ hC C ° Ur8e of the ®hip, keeping in mind that ' tw ' U n Mdur ^ 
of Lizard f ‘ f°, ra P ass that the observations will be made. Posts P . Jot» 
lt^ d bS th r W0Uld he “«.,«l. and also on the magnetic •’ 
denoting tbf 9 deDUtin S t,le north or south bearings, end ** 
that is S rh P “ agllct|t ' meridian, should be painted of different f® . thf 
rneridnn .V n ^ should be red ' while the latter, *ho* JJ “ vehfl r.^ 
Placed on thp U d ^• cl ‘ 0 1 UL,re<l - Great Ormshead and Holyhead should h 
bound. h ’ Wh ' ch Wou,d be o^ervablc to ships both outward an 
n ^* cto fj a l a*d Photochromatic Impressions on the *f. 
Eye. By the Rev. William Scorjmby, D.D., 
which prese a n r tedft d ', With much »>»«*««■ of detail, the jygjj, 
a moir,entarvl, ? ,Se,Ves to him after gazing fixedly for b feW^ 
objects_such^as T '■ a . ni >nute) on transparent, luminous or s a n | ' 
in'the^cloudt £ within a T' *£££** 
, &c. On closing the eyes, gently, with 
