16 Mr. J. Napier on the Solubility of the November 20 1843.-Robert Porrett Esq. Treasurer in the Chair. The following works were presented to the Society :- ‘ I Fresenius on Chemical Analysis,” translated and edited by Loyd A New Method of Alkalimetry,” by Drs. Fresenius and Will ; I‘ A Series of Chemical Tables and Labels,” by Messrs. Charles Bullock Esq. from the editor. translated and edited by Loyd Bullock Esq. from the editor. Button and Warren de la Rue from the authors. Taylor’s Calendar of the Meetings of the Scientific Bodies of London,” for 1843 and 1844 from the editor The following papers were then read :- LXXXVIII. On the Solubility of the Metals in Persdphate and Perchloride of Iron. By Mr. JAMES NAPIER. T have HE nished following state for observations some months past been in lying hopes in that an unfi- time would allow me to make more investigations into some of the phaenomena developed ; but owing to urgent duties altogether apart from such investigations I have little hopes of being able to fulfil these intentions; I have therefore collected them together in hopes that it might attract the attention of some one more qualified to give them that investigation which their singularity seems to deserve.I may be allowed in the first place to relate the circum- stances which led me to the observations which follow. Hear- ing of the great quantity of water which is constantly issuing from the Pary’s Mines Anglesea impregnated with copper and the great expense of obtaining this copper I thought it probable that it might be extracted by means of a galvanic current or what is known as the electrotype process.For the purpose of trying experiments upon this subject I was kindly favoured with a quantity of the water with the follow- ing details :-Quantity of water issuing from the mines yearly $oO,OOO,OOO gallons; this is collected in pits into which is put old iron which precipitates the copper. The average pro- duct of copper is from 55 to 60 tons; the iron consumed in obtaining this is 600 tons. The copper found in these waters as indicated from the precipitate obtained varies from 4 to 30 per cent. according to the wetness of the season ; the sam- ple I procured was during the dry season and consequently rich in copper; its specific gravity was 1*055 at 60’ F.The solid contents of one gallon weighed 4960 grains which gave Metals in Persulphate and Perchloride of Irou. peroxide of iron 1680 grains oxide of copper 80 grains sul- phuric acid 3040 grains muriatic acid 38 grains and 122 grains of earthy matters which were not examined. The iron existed in the water as the persulphate. My first operation was one I had found to answer in analysing copper ores namely wrapping a strip of brown paper round a piece of iron attaching this to a piece of copper and immersing them both in the solution of the copper ore in muriatic acid to be examined ; but I found that the first action which took place was the complete reduction of' the persalt of iron to the state of protosalt at the expense of the copper pole after which the electric current began to effect its object the copper being cleposited but from the copper which had been dissolved haying also to be deposited the consumption of iron was 658 grains while the actual increase in the weight of the copper pole was only 64 grains the quantity of copper originally held in solution.The reaction which took place may be expressed as follows :- . - sulphuric acid. oxygen acid acid acid copper Chem. Sue. filein. VOL. 11. protosulphate of iron. sulphate of copper. giving 690.7' grs. + 64 grs. to be ;lepositrd by the electric cur- Copper pole. rent. Different arrangements of batteries were tried; platinum silver and lead were also substituted for the copper but in no case was a deposit obtained from the water until the iron was first brought into the state of a protosalt; but when this was effected I obtained by the method first described 6 3 grains of copper by the loss of 58 grains of iron.Uuring these experiments I found that silver tin lead an- timony bismuth cobalt nickel and several other metals were very soluble in neutral persalts of iron reducing it to the state of a protosalt. In order to repeat these experiments I prepared sonie perchloride of' iron in the following manner adding to the boiling solution of the sulphate as much nitric acid as was necessary to peroxidize tile iron then precipitating by ammonia washing this well with hot water aiid dissolving with hydrochloric acicl evaporating nearly to dryness a i d adding a quantity of distilled water.'The persulphate used was obtained as a dry white powder; both salts were neutral. I was aware that Professor Fuchs had recommended the c 171-5 582.7 17 Mr. J. Napier on the Solubility of the 18 boiling of n piece of clean copper in perchloride of iron as a means of ascertaining the quantity of iron in an ore of that metal and also to ascertain the amount of copper in certain copper ores. For iron ores I have fi)und great difficulty in obtaining uniform results from the great difficulty of knowing the exact period at which the iron is all reduced to the proto state for the copper put in continues to dissolve until the chloride is all converted into a subchloride; this result is effected however much more rapidly when the iron salt is neutral than when it contains free acid a condition specially recommended by Fuchs.The most uniform results are obtained by allowing the copper to remain until the solution hecomes colourless ; on diliiting with cold water the whole of the copper is precipi- tated as a white powder ; the clear solution if the process is completed will contain no copper when there will be two equivalents of copper dissolved from the metal for every equi- valent of peroxide of iron formerly in the solution. I t occa- sionally happens however when neutral salts of iron are used that the copper becomes encrusted with a white deposit upon which crystals of the subchloride of copper collect and thus protect it from further action; this is prevented by boiling or taking out the copper removing the crust washing it and putting it into the solution again when the action goes on as before.When the persulphate of iron is used for this pur- pose instead of perchloride no subsalt is formed and the re- sult is uniform one equivalent of copper being dissolved for every equivalent of peroxide of iron present in the solution. I iiiay mention one especial application of the solubility of copper in perchloride of iron namely the dissolving copper from the surface of silver such as copper that has been used as c? mould in which silver has been deposited; when this so- lution becomes saturated with copper a little ammonia added precipitates the iron as a peroxide and combines with the copper forming a soluble double chloride which may be im- mediately separated by filtration and the precipitate washed the peroxide of iron again dissolved in hydrochloric acid is fitted for a renewal of the same operation.I may here men- tion that ic previous to adding theammonia there be a little perchloride of iron put into the mixture of subchloride of cop- per and protochloride of iron a n immediate change is effected the colour of the solution becomes green and on adding am- monia to this both copper and iron are precipitated. Persulphate of iron cannot be used for the purpose of dis- solving copper from silver both from the easy solubility of silver in solutions of this salt and also from a peculiar de- 19 Metals i7i Persulphate and Perchloride of Iron.structive action which it has upon alloyed silver. Standard silver is completely destroyed. I have used thin sheets weighing from 60 to 70 grains and when only 4 grains were apparently dissolved the remainder had been so much affected that it crumbled between the fingers like a dried leaf. When silver is put into a solution of persulphate of iron an immediate action takes place a yellowish cloud begins to form in the solution; if heated the action is much more rapid a yellow oxide of iron forming upon the sides of the vessel and there is also a brown precipitate deposited; the iron in the solution is converted into the proto state shining particles of metallic silver float through the solution and sulphate of sil- ver crystallizes 011 the vessel but in no case did l find an equivalent of silver for the equivalent of peroxide of iron ; by slow evaporation the solution yielded crystals of protosulphate of iron and sulphate of silver.Tin is very easily dissolved in both the persulphate and per- chloride of iron completely reducing them to the proto state. When the solution is cold this is effected in about an hour; when hot in a few minutes; the iron is reduced to the proto state when only half an equivalent of tin is dissolved for every equivalent of peroxide; my first impression was that the first atoms of protosalt of tin formed reduced a corresponding atom of peroxide of iron and was converted into a persalt; but sa- turating with ammonia and adding it in great excess the pre- cipitated oxide of tin was not redissolved and had every other character of a protosdt.Whether this was owing to the for- mation of a bisulphate or bichloride oytin I did not ascertain; but by boiling or long standing there is an equivalent of tin dissolved for every atom of perchloride of iron but I did not obtain the same result in the persulphate. Cadmium is very soluble in persalts of iron; in the persul- phate an equivalent of cadmium is dissolved for the equivalent of persulphate of iron ; but in perchloride of iron 2 equivalents of cadmium are dissolved for every equivalent of perchloride of iron forming as in the case of copper a subchloride which was not precipitated by the addition of water.Lead is also dissolved in persalts of iron reducing a portion of the iron to the state of a proto salt; the lead becomes co- vered with a thin crust of sulphate or chloride which seems to protect it from further action; when the iron solution is boiled with the lead much more is dissolved and a precipitate of peroxide of iron collects at the bottoni. This action of iron on lead may account for the rapid destruction of leaden tanks noticed by Mr. West at the last Meeting of the British As- sociation that when spring water which had been running c 2 Mr. J. Napier on ihe Solubility of the Netats. 20 into a lead tank for many years without the slightest action upon the lead was conveyed through iron pipes to the tanks the tanks were destroyed in six years.Aiztirnony is not very soluble in persulphate of iron even when heated but it is very soluble in perchloride of iron when hot reducing the iron to a protochloride in a short time the solution becoming of a light brownish colour. I found that if kept boiling slowly for a long time the antimony loses an equivalent of metal for every equivalent of peroxide of iron giviiig us the idea of the existence of'a compound of antimony with chlorine of one to one. l'his solution was not examined further than by dilution with water which precipitated almost all the antimony as a white powder undergoing the usual changes of comnioii chloride except when the dried precipi- tate was boiled in nitric acid in which it dissolved with the evolution of nitrous gas.I Arsenic is very soluble in perchloride of iron reducing the iron to the state of' protochloride losing also with long boil- ing an equivalent of metal for every equivalent of peroxid? of iron in the solution ; but this result is not obtained without long boiling. Bismuth is very soluble in perchloride of iron slightly in persulphate ; the perchloride i s coinpletdy reduced to the state of protochloride a full equivalent of metal being dis- solved for the peroxide of iron present ; this is wholly preci- pitated by dilution. Cobalt is very soluble in perchloride of iron reducing it completely changing the solution to a pink colour ; the co- balt salt tormed crystallizes from this solution very easily.Nickel is also soluble in perchloride of iron giving a pre- cipitate of brown oxide of iron ; the solution becomes green containing protochloride of iron and nickel; a portion of the nickel is precipitated as a fine white powder by dilution. PZatinum in persulphate and perchloride of iron produced no change neither lost anything in weight. Gold boiled for a long time in perchloride of iron in two experiments lost 0.2 and 0-3 of a grain. I n both these in- stances beautiful crimson-red crystals in perfect octahedrons were obtained adhering to the metal and also to the con- taining vessel. I did not try whether they contained any gold. These results were only obtained twice in six different trials; they were procured with iron prepared at different times.Platinum was always tried at the same time with the gold and when there was no gold dissolved I never obtained any crystals. 'I need hardly mention that both zinc and iron when put 21 Mr. J. N. Furze on Fermentation. into the persalts of iron first reduce the persalt to the pro- tosalt which fully accounts for the great consumption of iron for the small quantity of copper ohtained in these waste waters of mines and not as was geiierally supposed from the exist- ence of free acid ; the copper is never all precipitated from the water so long as persalts of iron exist in the solution. The presence of persalts of iron also prevents the deposition of the copper by a galvanic current ; the proportionate quantity of persalts of iron necessary to resist completely the deposition of copper was not ascertained.In no one case did I find any double salt formed between the iron and metal dissolved in it but when the solution con- taining them was evaporated the salts of the two metals cry- stallized separately. In all cases 'where the process is conducted cold the solu- tion of the metal takes place at the bottom of the vessel and progresses upwards; this is beautifully exhibited when a tall glass is used with a solution of perchloride of iron and a slip of copper reaching to the bottom; the solution first becomes green at the lower part and this advances slowly upwards till it reaches the top but before the change of colour reaches the top the bottom has become colourless from the formation of subchloride.I may observe that the whole of these remarks are only the prominent features noted down as they occurred without any idea of bringing them before the Society in this unfinished state; but having no hope of obtaining leisure for making further investigations I have given them as they are thinking that perhaps some one having more time and ability would repeat the experiments and produce something more definite. 16 Mr. J. Napier on the Solubility of the November 20 1843.-Robert Porrett Esq. Treasurer in the Chair. The following works were presented to the Society :-‘ I Fresenius on Chemical Analysis,” translated and edited by Loyd A New Method of Alkalimetry,” by Drs. Fresenius and Will ; I‘ A Series of Chemical Tables and Labels,” by Messrs.Charles Taylor’s Calendar of the Meetings of the Scientific Bodies of Bullock Esq. from the editor. translated and edited by Loyd Bullock Esq. from the editor. Button and Warren de la Rue from the authors. London,” for 1843 and 1844 from the editor, The following papers were then read :-LXXXVIII. On the Solubility of the Metals in Persdphate HE following observations have been lying in an unfi- T nished state for some months past in hopes that time would allow me to make more investigations into some of the phaenomena developed ; but owing to urgent duties altogether apart from such investigations I have little hopes of being able to fulfil these intentions; I have therefore collected them together in hopes that it might attract the attention of some one more qualified to give them that investigation which their singularity seems to deserve.I may be allowed in the first place to relate the circum-stances which led me to the observations which follow. Hear-ing of the great quantity of water which is constantly issuing from the Pary’s Mines Anglesea impregnated with copper, and the great expense of obtaining this copper I thought it probable that it might be extracted by means of a galvanic current or what is known as the electrotype process. For the purpose of trying experiments upon this subject I was kindly favoured with a quantity of the water with the follow-ing details :-Quantity of water issuing from the mines yearly, $oO,OOO,OOO gallons; this is collected in pits into which is put old iron which precipitates the copper.The average pro-duct of copper is from 55 to 60 tons; the iron consumed in obtaining this is 600 tons. The copper found in these waters, as indicated from the precipitate obtained varies from 4 to 30 per cent. according to the wetness of the season ; the sam-ple I procured was during the dry season and consequently rich in copper; its specific gravity was 1*055 at 60’ F. The solid contents of one gallon weighed 4960 grains which gave and Perchloride of Iron. By Mr. JAMES NAPIER Metals in Persulphate and Perchloride of Irou. 17 peroxide of iron 1680 grains oxide of copper 80 grains sul-phuric acid 3040 grains muriatic acid 38 grains and 122 grains of earthy matters which were not examined. The iron existed in the water as the persulphate.My first operation was one I had found to answer in analysing copper ores, namely wrapping a strip of brown paper round a piece of iron attaching this to a piece of copper and immersing them both in the solution of the copper ore in muriatic acid to be examined ; but I found that the first action which took place was the complete reduction of' the persalt of iron to the state of protosalt at the expense of the copper pole after which the electric current began to effect its object the copper being cleposited but from the copper which had been dissolved haying also to be deposited the consumption of iron was 658 grains while the actual increase in the weight of the copper pole was only 64 grains the quantity of copper originally held in solution.The reaction which took place may be expressed as follows :-oxygen . - acid acid acid sulphuric acid. Copper pole. copper protosulphate of iron. 582.7 171-5 sulphate of copper. giving 690.7' grs. + 64 grs. to be ;lepositrd by the electric cur-rent. Different arrangements of batteries were tried; platinum, silver and lead were also substituted for the copper but in no case was a deposit obtained from the water until the iron was first brought into the state of a protosalt; but when this was effected I obtained by the method first described 6 3 grains of copper by the loss of 58 grains of iron. Uuring these experiments I found that silver tin lead an-timony bismuth cobalt nickel and several other metals were very soluble in neutral persalts of iron reducing it to the state of a protosalt.In order to repeat these experiments I prepared sonie perchloride of' iron in the following manner, adding to the boiling solution of the sulphate as much nitric acid as was necessary to peroxidize tile iron then precipitating by ammonia washing this well with hot water aiid dissolving with hydrochloric acicl evaporating nearly to dryness a i d adding a quantity of distilled water. 'The persulphate used was obtained as a dry white powder; both salts were neutral. I was aware that Professor Fuchs had recommended the Chem. Sue. filein. VOL. 11. 18 Mr. J. Napier on the Solubility of the boiling of n piece of clean copper in perchloride of iron as a means of ascertaining the quantity of iron in an ore of that metal and also to ascertain the amount of copper in certain copper ores.For iron ores I have fi)und great difficulty in obtaining uniform results from the great difficulty of knowing the exact period at which the iron is all reduced to the proto state for the copper put in continues to dissolve until the chloride is all converted into a subchloride; this result is effected however much more rapidly when the iron salt is neutral than when it contains free acid a condition specially recommended by Fuchs. The most uniform results are obtained by allowing the copper to remain until the solution hecomes colourless ; on diliiting with cold water the whole of the copper is precipi-tated as a white powder ; the clear solution if the process is completed will contain no copper when there will be two equivalents of copper dissolved from the metal for every equi-valent of peroxide of iron formerly in the solution.I t occa-sionally happens however when neutral salts of iron are used, that the copper becomes encrusted with a white deposit upon which crystals of the subchloride of copper collect and thus protect it from further action; this is prevented by boiling, or taking out the copper removing the crust washing it and putting it into the solution again when the action goes on as before. When the persulphate of iron is used for this pur-pose instead of perchloride no subsalt is formed and the re-sult is uniform one equivalent of copper being dissolved for every equivalent of peroxide of iron present in the solution.I iiiay mention one especial application of the solubility of copper in perchloride of iron namely the dissolving copper from the surface of silver such as copper that has been used as c? mould in which silver has been deposited; when this so-lution becomes saturated with copper a little ammonia added precipitates the iron as a peroxide and combines with the copper forming a soluble double chloride which may be im-mediately separated by filtration and the precipitate washed, the peroxide of iron again dissolved in hydrochloric acid is fitted for a renewal of the same operation. I may here men-tion that ic previous to adding theammonia there be a little perchloride of iron put into the mixture of subchloride of cop-per and protochloride of iron a n immediate change is effected, the colour of the solution becomes green and on adding am-monia to this both copper and iron are precipitated.Persulphate of iron cannot be used for the purpose of dis-solving copper from silver both from the easy solubility of silver in solutions of this salt and also from a peculiar de Metals i7i Persulphate and Perchloride of Iron. 19 structive action which it has upon alloyed silver. Standard silver is completely destroyed. I have used thin sheets, weighing from 60 to 70 grains and when only 4 grains were apparently dissolved the remainder had been so much affected that it crumbled between the fingers like a dried leaf. When silver is put into a solution of persulphate of iron an immediate action takes place a yellowish cloud begins to form in the solution; if heated the action is much more rapid a yellow oxide of iron forming upon the sides of the vessel and there is also a brown precipitate deposited; the iron in the solution is converted into the proto state shining particles of metallic silver float through the solution and sulphate of sil-ver crystallizes 011 the vessel but in no case did l find an equivalent of silver for the equivalent of peroxide of iron ; by slow evaporation the solution yielded crystals of protosulphate of iron and sulphate of silver.Tin is very easily dissolved in both the persulphate and per-chloride of iron completely reducing them to the proto state. When the solution is cold this is effected in about an hour; when hot in a few minutes; the iron is reduced to the proto state when only half an equivalent of tin is dissolved for every equivalent of peroxide; my first impression was that the first atoms of protosalt of tin formed reduced a corresponding atom of peroxide of iron and was converted into a persalt; but sa-turating with ammonia and adding it in great excess the pre-cipitated oxide of tin was not redissolved and had every other character of a protosdt.Whether this was owing to the for-mation of a bisulphate or bichloride oytin I did not ascertain; but by boiling or long standing there is an equivalent of tin dissolved for every atom of perchloride of iron but I did not obtain the same result in the persulphate. Cadmium is very soluble in persalts of iron; in the persul-phate an equivalent of cadmium is dissolved for the equivalent of persulphate of iron ; but in perchloride of iron 2 equivalents of cadmium are dissolved for every equivalent of perchloride of iron forming as in the case of copper a subchloride which was not precipitated by the addition of water.Lead is also dissolved in persalts of iron reducing a portion of the iron to the state of a proto salt; the lead becomes co-vered with a thin crust of sulphate or chloride which seems to protect it from further action; when the iron solution is boiled with the lead much more is dissolved and a precipitate of peroxide of iron collects at the bottoni. This action of iron on lead may account for the rapid destruction of leaden tanks, noticed by Mr. West at the last Meeting of the British As-sociation that when spring water which had been running c 20 Mr.J. Napier on ihe Solubility of the Netats. into a lead tank for many years without the slightest action upon the lead was conveyed through iron pipes to the tanks, the tanks were destroyed in six years. Aiztirnony is not very soluble in persulphate of iron even when heated but it is very soluble in perchloride of iron when hot reducing the iron to a protochloride in a short time the solution becoming of a light brownish colour. I found that if kept boiling slowly for a long time the antimony loses an equivalent of metal for every equivalent of peroxide of iron, giviiig us the idea of the existence of'a compound of antimony with chlorine of one to one. l'his solution was not examined further than by dilution with water which precipitated almost all the antimony as a white powder undergoing the usual changes of comnioii chloride except when the dried precipi-tate was boiled in nitric acid in which it dissolved with the evolution of nitrous gas.I Arsenic is very soluble in perchloride of iron reducing the iron to the state of' protochloride losing also with long boil-ing an equivalent of metal for every equivalent of peroxid? of iron in the solution ; but this result is not obtained without long boiling. Bismuth is very soluble in perchloride of iron slightly in persulphate ; the perchloride i s coinpletdy reduced to the state of protochloride a full equivalent of metal being dis-solved for the peroxide of iron present ; this is wholly preci-pitated by dilution.Cobalt is very soluble in perchloride of iron reducing it completely changing the solution to a pink colour ; the co-balt salt tormed crystallizes from this solution very easily. Nickel is also soluble in perchloride of iron giving a pre-cipitate of brown oxide of iron ; the solution becomes green, containing protochloride of iron and nickel; a portion of the nickel is precipitated as a fine white powder by dilution. PZatinum in persulphate and perchloride of iron produced no change neither lost anything in weight. Gold boiled for a long time in perchloride of iron in two experiments lost 0.2 and 0-3 of a grain. I n both these in-stances beautiful crimson-red crystals in perfect octahedrons, were obtained adhering to the metal and also to the con-taining vessel.I did not try whether they contained any gold. These results were only obtained twice in six different trials; they were procured with iron prepared at different times. Platinum was always tried at the same time with the gold and when there was no gold dissolved I never obtained any crystals. 'I need hardly mention that both zinc and iron when pu Mr. J. N. Furze on Fermentation. 21 into the persalts of iron first reduce the persalt to the pro-tosalt which fully accounts for the great consumption of iron for the small quantity of copper ohtained in these waste waters of mines and not as was geiierally supposed from the exist-ence of free acid ; the copper is never all precipitated from the water so long as persalts of iron exist in the solution.The presence of persalts of iron also prevents the deposition of the copper by a galvanic current ; the proportionate quantity of persalts of iron necessary to resist completely the deposition of copper was not ascertained. In no one case did I find any double salt formed between the iron and metal dissolved in it but when the solution con-taining them was evaporated the salts of the two metals cry-stallized separately. In all cases 'where the process is conducted cold the solu-tion of the metal takes place at the bottom of the vessel and progresses upwards; this is beautifully exhibited when a tall glass is used with a solution of perchloride of iron and a slip of copper reaching to the bottom; the solution first becomes green at the lower part and this advances slowly upwards till it reaches the top but before the change of colour reaches the top the bottom has become colourless from the formation of subchloride. I may observe that the whole of these remarks are only the prominent features noted down as they occurred without any idea of bringing them before the Society in this unfinished state; but having no hope of obtaining leisure for making further investigations I have given them as they are thinking that perhaps some one having more time and ability would repeat the experiments and produce something more definite