Jan. 6. 1855.] 



NOTES AND QUERIES. 



15 



of his memory and judgment better than could 

 have been expected. His partner in life is yet 

 healthy and active for her years. _ ^ • 



A better example of a shrewd intelligent couple 

 could not easily be seen ; who, while they were 

 able to follow their ordinary occupation, were in- 

 dependent and hard-working. It would trespass 

 too much on space to give any history of " Old 

 George," as he is familiarly called. In the prime 

 of life he was many years engaged as a man-of- 

 war's man ; served with Sir Sidney Smith at St. 

 Jean d'Acre, where he was wounded in the arm ; 

 and was concerned in most of the exploits of 

 Nelson, and at the battle of the Nile. Afterwards 

 he voluntarily left the service; and for having 

 done this, he says he was not entitled to any pen- 

 sion or other government assistance. 



The thatched cottage in which he resides is also 

 a relic of by-gone times, it having been a way- 

 side hostelrie in 1745, kept by Janet Stobo ; at 

 which Prince Charles halted and refreshed, on his 

 inarch with the rebel troops from Glasgow to 

 Stirling on the morning of Jan. 3, 1746. In the 

 tout ensemble of this scene, truth appeals more 

 powerfully than any kind of fiction. You enter 

 the cottage, and see the aged couple by the fire- 

 side reading the Bible and Instructive books, their 

 almost constant employment ; and hoping, with 

 Christian resignation, that their " time will not be 

 long now." With all the vivacity of a young hero, 

 ills dim eyes glistening full of tears, George will 

 describe to the young listeners around. Nelson and 

 the fleet, and fight his battles over again. He has 

 always been a little thin man, endowed with a 

 highly nervous active temperament. 



If there was any fund In London applicable to 

 such cases, a very small allowance would be ex- 

 tremely beneficial in smoothing the few remain- 

 ing days of this interesting couple, and would be 

 judiciously bestowed. G. N. 



PHOTOGKAPHIC COBBESPONDENCE. 



Sromo-iodide of Silver. — I see by a letter pubHshed in 

 "N. & Q." of last week, that Mr. Reade states that a 

 real bromo-iodide of silver is formed by the solution of 

 bromide of silver in iodide of potassium, and that he finds 

 fault with a former letter of Mr. Leachman's on this 

 subject. Now there may be, as I allow, a difference in 

 the molecular arrangement of iodide of silver deposited on 

 the paper, and thus a more perfect impression produced 

 of greens, or even yellows ; but that there exists even the 

 least trace of bromide of silver in the deposit, I entirely 

 deny. To prove this let me only ask that Mr. Reade 

 will do me the favour of trying the following experiments. 

 Take three grains of nitrate of silver, and three grains of 

 iodide of potassium ; dissolve separately ; then add them 

 together, and wash the precipitate thus produced with 

 distilled water ; drain as dry as possible, and add half an 

 ounce of liquid ammonia fort. ; let them digest together 

 for several hours, shaking occasionally, and filter the so- 



lution repeatedly till quite clear ; next repeat the same 

 experiment with only the substitution of bromide of po- 

 tassium for the iodide above mentioned ; place the two 

 solutions apart in separate test tubes. Next take the so- 

 lution as recommended by Dr. Diamond and Mr. Reade, 

 and adding water to precipitate the so-called bromo- 

 iodide of silver, collect the precipitate on a filter ; wash it 

 well, and digest it with ammonia as before ; filter the 

 liquid, and place it in another test tube. Now to each of 

 these add an excess of dilute nitric acid ; the result will 

 be that the first will become only in the smallest possible 

 degree opalescent, if at all so. The second will become 

 quite white with the precipitate produced, while the 

 third will show exactly the same comportment as the 

 first. This establishes that we have a method of detecting 

 bromine and iodine separately ; and also that in the case 

 of Mr. Reade's bromo-iodide of silver, it comports itself 

 with ammonia as iodide of silver does. But, he will say, 

 does that prove that this is not bromo-iodide of silver ? 

 Yes, it does, by the following experiment : first, mix in 

 solution three grains of iodide of potassium, and two of 

 bromide of potassium ; add nitrate of silver in slight ex- 

 cess, and then well wash the precipitate in a dark room ; 

 digest this, as before, in ammonia, and on the addition of 

 an acid the same result is obtained as in the case of pure 

 bromide of silver, that is to say, complete milkiness of the 

 liquid. The reason for using the above proportions is, 

 that this is the proportion, or nearly so, in which iodine 

 and bromine combine separately ; and so we may expect, 

 from similar examples occurring in chemistry, that this 

 is their proper proportion of combination with bases ; but 

 should this not satisfy Mr. Re.vde, let him add the least 

 possible amount, instead of the above-named quantity of 

 bromide, and he will always find that it at once produces 

 extra milkiness in direct proportion to the quantity of 

 bromide added, when compared with the almost complete 

 transparence of the solution produced by what he chooses 

 to call bromo-iodide of silver. Now I am far from saying 

 that there does not exist such a compound as bromo- 

 iodide of silver, but only that this is not the way to 

 make it ; nor would I for the world detract from the value 

 of Dr. Diamond's discovery, by which these troublesome 

 green tints may be impressed ; all I say is, that this is 

 not the way to get bromo-iodide of silver, as all the 

 bromine remains in solution. But now for the method to 

 get the substance required. The only means I know of 

 is a modification of a process which appeared some time 

 since in " N. & Q." Take fifty grains of iodide of potas- 

 sium, and fifty grains of nitrate of silver ; mix in separate 

 portions of distilled water ; pour them together, and col- 

 lect and well wash the precipitate. Next take fifteen 

 grains of bromide of potassium, and fifteen grains of nitrate 

 of silver, and treat them in a similar manner. Mix the 

 two precipitates thus produced in a measure glass, and 

 fill the latter to mark six ounces with distilled water. Now 

 add very carefully, in very minute portions at a time, and 

 in fine powder, some cyanide of potassium, till the liquid 

 only jtist clears up, and then filter it. The best cyanide 

 for the purpose is that purified by crystallisation froni 

 alcohol, as the ordinary cyanide contains much free alkali, 

 and acts injuriously on the paper ; it will, however, do in 

 default of better. The paper is to be laid as usual on this 

 liquid, and when it has thoroughly imbibed, to be taken 

 off; when nearly dried, throw it into a bath of a quart of 

 distilled water, to which has been added one or two 

 ounces of glacial acetic acid. By this means the cyanide 

 is decomposed, and the iodide and bromide of silver pre- 

 cipitated together. I prefer not using more bromide than 

 above indicated, as it makes the colour of the negative 

 rather too red when finished ; but it may be increased at 

 the pleasure of the operator, or the whole quantity of the 



