MR. H. hf. WI'PT OX 111.-Analysis of the Ash of Lemon-Juice. BY HENRYM. WITT Assistant in the Royal College of Chemistry (the Laboratories of the Metropolitan School of Science.) The following analysis having for its object the determination of the mineral constituents in the juice of lemons was made during the early part of last surnmer in the laboratory of the Royal College of Chemistry under the superintendence of Dr. Hofmann and at the request of Dr. Bence Jones. Preparation of the Ash.-The lemons (200 in number} were peeled with a bright steel knife care being taken in so doing to avoid as much as possible cutting into the juicy endocarp and thus bringing the acid in contact with the steel knife; the juice was then expressed by a hand-squeezer of wood (without any metallic hinges) and filtered through flannel into a porcelain dish in which it was evaporated to the condition of a black carbonaceous mass then transferred a portion at a time into a platinum dish and ignited until perfectly white.A qualitative exurnination was first made which indicated the presence of potassa soda lime magnesia and sesquioxide of iron; of silicic phosphoric sulphuric hydrochloric and carbonic acids. A separate and very careful examination was made for alumina but it was not detected; manganese was also separately tested for but not found. As regards the plan followed in performing the quantitative analysis it differed in no respect from that generally adopted. Without entering into details it may be stated that the part insoluble in hydrochloric acid consisted of silica and carbonaceous matter.In one portion of the hydrochloric solution the phosphate of iron the lime magnesia and phosphoric acid were determined ; whilst separate portions of the solution were employed for the alkalies and for sulphuric acid ; a nitric acid solution being used for the determination of hydrochloric acid ; and lastly a distinct portion of the ash was reserved for estimating the carbonic acid. The phosphoric acid was determined as ammonio-magnesian-phosphate in the dilute solution to which acetate of potassa had been added after separation of the lime by oxalic acid. The following are details of the results obtained. 1. Determination of silica. Weight of ash employed.Silica obtained. Percentage. I. 593835 grns. 11. 23.6165 , 0.355 grn. 0.128 , 0.5986 0.542 THE ANALYSIS OF TRE ASH OF LEMON-JUICE. 45 2. Determination of carbon. Weight of ash employed. Carbon obtained. Percentage. I. 59.3835 grns. 0,0615 grn. 0.1035 3. Determination of phosphate of iron. Weight of ash employed. Phosphate of iron obtained. Percent age. I. 24.5077 grns. 0.230 gm. 0.9385 11. 18.276 , 0.219 , 1-198 4. Determination of lime. Weight of ash employed. Carbonate of linie obtained. Percentage of litne. I. 24.5077 gms. 3.354 grns. 7-6631 11 18.276 , 1.353 , 7.4059 5. Determination of magnesia. Pyrophosphate of Percentage of Weight of ash employed. magnesia obtained. magnesia. I. 18.276 gms. 1.644 grnu.3 2124 11. 23.6165 , 2.12385 , 3.385 6. Determination of'phosphoric acid. a. In combination with lime Pyrophosphate of Percentage of Weight of ash employed. magnesia obtained. phosphoric acid. I. 18.276 grns. 0.402 grns. 1*el46 11. 16242 , 0520 , 2.0582 p. In combination with magnesia Pyrophosphate of Percentage of Weight of ash employed. magnesia. phoPphoric acid. I. 18.276 gms. 1.644 gms 5.7825 11. 23.616 , 2.2385 , 5.7106 7. Determination of the alkalies. r. 11. Weight of ash employed . . 10.86 gms. 11.948 gms Weight of mixed chlorides obtained. 7.970 , 9.04 , Corresponding to per cent of mixed 45.9355 45.9446 alkalies (KO and NaO) . -1 Weight of potassium platinum-salt } 25.077 , 26.700 ,, (KCI PtCI,) obtained hence Percentage of potassa .. 44.251 , 443.545 Y> soda . 1.6845 , 12.3996 8. Determination of sulphuric acid. Sulphate of Percentage of Weight oi azh employed. 1)aryta obtained. siilphuric acid. 1. 8.7795 6""s. 3.159 gr17s. 12.354 TI. 6.018 , 2.069 ,) 11.8ofL MR. U. M. WITT ON 9. Determination of carbonic acid. Weight of ash employed. Carbonic acid evolved. Percentage. I. 15.517 gms. 3-02grns 19-46:! 10. Determination of chlorine. Weight of ash employed. Chloride of silver obtained. Percentage. I. 8.7795 grns. 0.429 grns. 1.2079 grns. 11. 6,018 , 0.295 , 1.2090 , The following table is a synopsis of the preceding results I. 11. mean. Alkalies (KO and NaO) 45.9355 45.9446 45*9400 Potassa . 44251 43.545 43.8984 1 *6845 2.3996 2.1416 Soda .7.6631 7.4059 7.5345 Lime Magnesia . 3.2124 3.385 32987 Sulphuric acid . 12.3540 -12.3540 Chlorine . 1*200 1.2079 1*2084 Carbonic acid . 19.462 -19.4620 Phosphoric acid . 7.1971 7-7691 7.4829 Phosphate of iron . 0.9385 1.198 1.0682 05986 0.542 0*5700 Silica . Carbon . 0.1035 0,1035 *lumina f absent. Manganese 99.1222 The preceding numbers after deducting the charcoal give the following as the percentage composition of the ash Potassa . . 44-34? Soda . . 2.16 . 7*6l Lime 3lagnesia . . 3.34 Sulphuric acid . . 12-47 Carbonic acid . . 1966 Chlorine . . 1.23 Phosphoric acid . . 7.56 Phosphate of iron . . 1'06 Silica . . 057 100.00 THE ANALYSIS OF THE ASH OF LEMON-JUICE.These constituents may be assumed to be thus arranged Carbonate of potassa . . . 57.725 Carbonate of soda . Sulphate of yotassa . Chloride of sodium . Sulphate of lime . (Tribasic) Phosphate of lime . Phosphate of magnesia . Phosphate of iron . Silica . 2.265 9.293 2.026 13935 3.687 9.086 1*06O 0.570 99,647 In order to ascertain the proportion of ash in the juice a known weight was carefully incinerated in a platinum dish with the following results Weight of juice employed. Ash obtained. Percentage. I. 587.96 grns. 3-11 grns. 0.52 11. 1020.695 , 2-055 , 0.20-Mean 0.36 Hence by calculation the following was obtained as the proportion of the several inorganic constituents of the juice Inorganic constituents of an ounce Troy (480 grns.) Inorganic constituents of 1000 grains of the juice.of the juice. 0.767 grns. 0.038 , 0.131 , 0,058 , 9.215 , 0.022 , 0.339 , 0.130 , 0.018 , 0.010 , 1.728 Potassa Soda Lime . Magnesia . Sulphuric acid Chlxine . Carbonic acid 1*597grns. 0-077 0.274 0.120 0.448 0.045 0.707 , , , , , 1 . . . . . . . Phosphoric acid . Phosphateof iron Silica . . 0.273 , 0.038 , 0.021 ,) Total 3.600 On reviewing thc above-nientioned results it was felt that the objection might by raiscd that either thc whole or at. least a portion MR. HEKRY HOW ON of the iron found might have been derived from the knife employed in cutting the lemons (notwithstanding the precautions taken to avoid contamination from this source) ;consequently to remove all doubt on this rather important point a fresh portion of juice was in-cinerated the lemons whence it was obtained having been cut with a silver knife and every possible care taken to avoid the extraneous introduction of iron.In the ash thus obtained the determination of the ferruginous phosphate was repeated with the following result Weight of ash Phosphate of iron employed. obtained. Percentage. 8.225 grns. 0.12gm. 1.458 which on comparison with the preceding lead to the conclusion that none of the iron had been derived from the knife since this last deterniination indicates a still larger proportion of the phosphate than either of the former determinations.