AN HISTORIC KIT FOR BLOWPIPE ANALYSIS SIDNEY M. EDELSTEIN Dexter Chemical Corporation, New York City
TEEusefulness and high regard with which blowpipe analysis was held in the middle of the last century is summed up in the following extract from a widely used textbook of chemistry of that period: "The mouth blowpipe is one of the most valuable and portable instruments of research which the chemist possesses; he is enabled by its means to arrive with certainty and economy a t results which without its aid would require much expenditure both of fuel and time, and it often affords information which could be obtained in no other way (I)." Surely a method which was so well considered in the past merits our examination today. In order to obtain a many sided view of blowpipe analysis, however, we shall do more than examine just the method. We shall also look a t its history and at a typical analytical chemist of the past century. As a final bit of intimate association we shall examine this particular chemist's own assay kit. THE METHODS OF BLOWPIPE ANALYSIS
Blowpipe analysis rests mainly on the indications afforded by substances when submitted to the oxidizing or reducing action of certain parts of a flame modified by a current of air. The itself is a small tube six to eight inches long and containing a fine orifice a t one end. BY blowing a stream of air through the larger end a h e but intense jet of air is emitted from the orifice, and when directed the flame a Or lamp an intense heat is developed over a minute area. The sample to be analyzed by this is subjected to various operations with the blowpipe such as heating on charcoal and on platinum with borax, microcosmic salt, and with a standard group of rea-
gents consisting of such materials as sodium carbonate, cobalt solutiou, sodium hyposulfite, zinc, potassium acid sulfate, and others. The reactions of the sample when heated in closed and open glass tubes are also noted. In general the tests may be carried out on a particle as small as a mustard seed. From the results of these tests the analyst can determine definitely, by reference to his own experience or to special tables, the inorganic constituents of the sample. If the material is a definite mineral he can positively identify the mineral by a few simple confirmatory tests. HISTORY OF BLOWPIPE ANALYSIS
The origin of the blowpipe is lost in antiquity. That this instrument was recognized and used in the arts in very ancient times is unquestioned. Egyptian carvings dating from 2500 B.C. clearly shorn the use of the blow~ i u hv e goldsmiths and other artisans. Even the word ioi sditrh, nuppaehu, in ancient Babylonian was derived from the name of the reed blow pipe (3). of this instrument in the arts for thouwith the sandsof years, one would expect that artisans and others would have made use of it to prove or test metals, ores, and minerals. Surprisingly, it was not until comparatively recent times that we have any record of the blowpipe being used for this purpose, Bartholin was probably the first to indicate that the blowpipe could be used for test purposes, rn his treatise on Iceland Spar, published in 1670, he states that this mineral is burned to lime before the blowpipe (8). Kopp points out, however, that Kunckel apparently the usefulness of the blolvpipe in chemical experiments about the same time. In ICunckel's "Ars vitraria ~ ~ ~ ~ ~ iit ~is mentioned ~ ~ t ~that l ai ~ , f l blower's table is very useful to the chemist, as f i r example in testing a metallic calx; "it is only necessary to hollow out a coal, put a small piece of the calx in the hole and blow on it with the flame of a lamp, and thus obtain the metal (4)." On the authority of Bergman we may attribute the first active use of the blowpipe as an instrument of chemical analysis to Anton Von Swab, a Swedish Metallurgist and Counselor of the College of Mines, about 1738. Von Swab, however, left no written work on this subject and it is not known how far he actually carried his studies (5). Johann Andreas Cramer (171&77), a German mining expert, was undoubtedly the first to record the usefulness of the blowpipe in assay work. I n his "Elementis Artis Docimasticae," which appeared in 1739, he
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Figure 2.
h a y Kit Open and Trey Removed
recommended the instrument for melting small bits of drawing the attention of mineralogists and chemists to metal and for testing quickly small grains of ores and the possibilities of this new method of analysis (10). At about the same time the great Swedish chemist, minerals. Cramer mas also the first to use borax in fuBergman, also entered this rapidly progressing field of sibility experiments before the blowpipe (6). When the great mineralogist Cronstedt (1722-65) analysis and soon outstripped his predecessors. Bergdescribed a new species of mineral before the Swedish man went further than Cronstedt and extended the Academy in 1756 and gave it the name of zeolite, his use of the blowpipe beyond the bounds of mineralogy attachment to the blowpipe as an analytical instru- into the field of inorganic chemistry. Bergman imment was obvious. For the word zeolite is a combina- proved the instruments, taught the difference between tion of two Greek words meaning to froth and stone. the oxidizing and reducing flames, and examined a Thus the results of the test of this mineral before the large number of minerals and inorganic compounds. blowpipe became its actual name which it bears even His. work on the subject was published in sections beginning in 1773 and finally in a collected form in Vienna to this day (7). This retiring genius, who laid the foundations of in 1779 under the title of "Commentatio de Tubo Ferrumineralogy, used the blowpipe as a means of studying minatorio" or "Treatise on the Blowpipe (If)." On account of his health, Bergman was assisted in the chemical relationships of the minerals. In these tests he employed borax, sodium carbonate, and micro- his work by Johann Gottlieb Gahn (1745-1818) who cosmic salt, and he was the first to make a portable kit is perhaps best known as the teacher of Berzelius. containing all the utensils and reagents needed for Gahn particularly applied himself to the use of the blowpipe in his mineralogical studies and, under Bergman, blowpipe analysis. Cronstedt only published such information on his he examined all the known minerals under this instruwork with the blowpipe as might serve to distinguish ment. I t is said that Gahn was so devoted to the blowminerals. Because the first edition of his work on pipe that he always carried one about with him and mineralogy was published anonymously, in 1758, much submitted everything to it that might possibly be tested. Perhaps the best known story of Gahn's skill with the of Cronstedts' work was accredited to others (8,9). It is to Gustav Von Engestrom (173&1813) that we blowpipe is that of Berzelius, in which the latter says are chiefly indebted for a knowledge of Cronstedt's work that long before it was known that the ashes of vegetable with the blowpipe. Von Engestrom gave an account of matter contained copper he (Berzelius) had seen Gahn Cronstedt's work with the blowpipe in his translation extract distinct particles of metallic copper from a sheet into English of the latter's mineralogy in 1770. This of burnt paper by means of the blowpipe (12). first complete manual on the use of the blowpipe was Gahn gave the blowpipe the basic form it still has translated into other langnages and was influential in today. He int,roduced the use of platinum wire as a
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pended on analytical chemistry a t a time when blowpipe analysis was widely used. Also his l i e and work are fairly well known and he studied analytical chemistry under Wohler, who in turn had studied under Berzelius. Finally we have before us the actual blowpipe assay kit used by Booth, and perhaps even made by him. In the middle of the year 1832, Booth, then a young man of 22 set sail from America for Europe, for the famous laboratory of Wohler a t Hesse-Cassel. Booth was probably the first American to venture to Germany for the purpose of studying analytical chemistry. While he had studied a t the University of Pennsylvania and had obtained his degree from this institution in 1829, apparently Booth was not able to obtain the desired training and hence ventured abroad. Wohler himself was a young man of thirty-two when Booth came to study under him. While Wohler was then directing his energies into the field of the infant organic chemistry, he was still full of the analytical training obtained under the master of analysis and of the blowpipe, Berzelius. Undoubtedly a t HesseCassel, Booth concentrated on analysis and probably learned the blowpipe technique and methods of Berzelius directly from Wohler. JAMES CURTIS BOOTH Booth wanted to continue study under Berzelius As our typical analytical chemist of the last century, himself, but even with a recommendation from Wohler we have chosen James Curtis Booth, because most of he was disappointed. Berzelius had discontinued rehis work in chemistry, mineralogy, and industry de- ceiving students because of his advanced age.
support and cobalt solution as a reagent. Finally he developed the method of reduction of metallic oxides with the aid of sodium carbonate on charcoal. Gahn published nothing on the subject other than a short treatise attached to Berzelius' "Elements of Chemistry (lS)." It is mainly through the writings of Berzelius that we have been made aware of Gahn's accomplishments. Berzelius for ten years was Gahn's pupil and friend. All that Gahn had learned about the blowpipe was passed on to and was enlarged upon by his apt pupil. Through Berzelius, blowpipe analysis became a standard method in both inorganic chemistry and mineralogy. The results of Berzelius' work and that of his predecessors, culminated in the publication of his classical treatise on the blowpipe in Sweden in 1820. This work was translated into many languages and into many editions ( 1 4 . The methods of analysis as given in this book have remained essentially unchanged except in minor details down to our own times. The field was further enriched, however, in these minor details by Berzelius himself, Le Baillif, Smithson, Turner, Harkort, Plattner, Richter, and others (16).
Kgure 3. Assag instruments from Assay Kit
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was able to meet promptly every demand."
Booth continued his active work in the field of industrial chemistry and remained as melter and refiner a t the Mint until 1888, the year of his death. According to Edgar F. Smith (16) the three great achievements of Booth's life were: (1) The foundation of a great laboratory of practical chemistry; (2) his splendid contribution to the geology, not only of his native state, but to that of the State of Delaware; (3) the most difficult of all, the conduct of the melting and relining at the mint in Philadelphia. In this last undertaking every faculty possessed by him was called into requisition. The work was done virtually in retirement. I t was not heralded to the world. It was
J. C. Booth
Upon his return to America, Booth founded a lahoratory for the instruction of men in industrial and analytical chemistry, and this laboratory developed into the well-known consulting firm of Booth, Garret, and Blair. Booth's interest in mineralogy and geology led to his appointment to the first geological survey of Pennsylvania and then as state geologist of Delaware. It is most likely that the assay kit was his constant companion on his mineralogical surveys and one can picture the young chemist at a table in some inn, in the evening after a days collecting of minerals, carefully testing some of the samples. In the hectic days of 1849 Booth was appointed melter and refiner of the Philadelphia Mint. The difficulties which Booth had to conquer seemed almost unsurmountable. The gold which was received a t the mint in its native state required prompt and accurate treatment to snit it for coinage. I t was also necessary to extract the excess of silver in the gold to fit it within the prescribed limits for gold coins. While the equipment at the mint had been perfectly satisfactory for handling the gold received hefore the California discovery, it m s now completely inadequate and Booth had to supervise the building of new equipment and the development of new processes. All of the difficulties Tvere overcome, and finally "under Booth's energetic and capable management, the mint
I'igure
a.
Blowpip. Assembled for Use
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Figure 5.
Contents of Right Portion of Kit
one of those contributions vhich only the well-equipped, conscientious, self-sacrificing individual can make. Therefore, too much credit cannot be given to Booth for his admirable outlay of energy and thought, extending over many anxious years. We may reasonably assume that Booth's knowledge of blowpipe analysis as well as his little assay kit served him as much in the third accomplishment as it undoubtedly did in the second.
The assay instruments are contained in the left portion of the kit. Each instrument is finely made and fits snugly into its own carved out space. Most of these instruments are exactly as described in Berzelius's book on the blowpipe published in 1820. The blowpipe itself is a pocket type invented by Mitscherlich (see item 1 in Figures 2 and 3). It is simply Gahn's blowpipe in compact form. It consists of two silver-plated brass tubes which screw together and a small tip of silver which fits in a t one end. FigBOOTH'S ASSAY KIT ure 4 shows the assembled blowpipe; a and b are the Let us now examine Booth's assay kit (Figure 1). two silver-plated brass tubes, c is the silver tip, d is the This beautiful little outfit was found among some of moisture trap invented by Gahn which prevents conBooth's effectswhich were auctioned off in Philadelphia densate from spewing over the assay. The operator a few years ago by Booth's aged daughter. either blew directly into the blowpipe . . or used a special The box is apparently made from a single piece of mouthpiece, e. walnut and is 43/, in. wide, 91/4 in. long and Za/, in. In the left portion of the kit as shown in Figure 2, high. As one can see, it is about the size of a thick there are about twenty instruments each of which has octavo volume. a special job to do. The brass plate a t the front end contains a double These assay instruments are displayed in Figure 3. lock. The box opens on hinges a t the other end to Mineral samples are broken on the steel anvil (2), with display all the reagents on the one side and all the instru- the small hammer (3), or filings are taken with the file ments on the other, required to make a complete quali- (4). The small sample pieces are handled with the tative inorganic andysis (Figure 2). steel forceps ( 5 ) , or with the smaller one of brass (6).
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If a small sample is to be held in the flame for test the copper oxide, copper fluoride, silica and nickel oxide. platinum end of the brass forceps (6a) serves well. Test papers, metal foils which were used as sample Ore samples are roasted in the small covered crucible supports, and glass tubes are also present. (7) over an alcohol lamp (8). The kit contains a colIn the right-hand portion of the kit are the four main lapsible stand (9) which consists of three parts made of fluxes in wooden boxes. These are sodium carbonate, German silver. A crucible support (10) equipped with sodium phosphate, borax, and potassium nitrate. a swivel joint (10a) and an oil lamp (11) fit snugly Most of the reactions with the blowpipe were carried on the stand. It should be noted how well made each out on the blocks of charcoal. of these pieces are. Figure 5 is another view of the contents of the tray Generally hardness tests were made on mineralogical and the right-hand portion of the kit. Numbers (1) samples and a knife (12) is provided for these tests. and (2) are the fluxes and solid reagents; (3) the various For comparisons, minerals having different degrees of hardness are a t hand in the little wooden box (13). This glass tubes required in the assay work; (5) a charcoal box serves another use as do many of the other in- block; and (6) is the metal holder for the charcoal. struments in the box. The magnetic and electrical Lead, platinum, and tin foil are represented by items properties of minerals are helpful in their analysis and (7) and (8). Number (9) is a dropping bottle for coso complete equipment is provided for the testing of balt solution; (10) platinum wire; (11) litmus paper; these properties. The top of the box serves as a holder and (4) consists of small watch glasses, three of glass for a needle (13a) on which may float freely a jeweled and one of ivory. Finally, item (12) is a bottle of old magnetic needle (14), or a brass needle (15) which may fashioned phosphorus matches which completes the kit. be charged with positive or negative electricity. For most of the tests with fluxes the sample must be in a h e form and so the anvil (2) doubles as a p u l v e ~ LITERATURE CITED iaer, and for h e grinding an agate mortar and pestle (1) MILLER, W. A,, "Elements of Chemistry," Parker, London, (16) are provided. In Figure 3 the anvil is shown in 1860, p. 258. reverse presenting the side which acts as a receptacle (2) PARTINGTON, J. R., "Origins and Development of Applied for the steel pestle (17). Chemistry," Longmans, London, 1935, pp. 15,258. For examining samples closely we have a double lens K. F., "Plilttner's Manual of Qualitative and (3) PLATPNER, magnifying glass (18). A spatula (19) and spoons of Quantitative Analysis with the Blowpipe!' Translated bv H. B. CORNWALL. Van Nostrsnd Ca.. New York. ivory (20) and platinum (21) are also provided. Nurnbers (22) and (23) are parts of the ivory mouthpiece (4) KOPP,H., "Gesohichte der Chemia," Vieweg, Braunsrhfor the blowpipe. Number (24) is a needle holder useweig, 1844, p. 44. ful for many purposes. J. J., "The Use of the Blowpipe in Chemical (5) BERZELIUS, Analysis and In the Examination of Minerals!' TransThe tray shown a t the top of Figure 2 contains most Baldwin, London, 1822, p. 2. lated by J. G. CHILDREN, of the special reagents used in blowpipe analysis. Each (6) KOPP.H.. "Geschiehte der Chemie!' Vieweg. -. Braunschweig. -. of these reagents is kept in a nicely carved ivory bottle 1844, d. 45. with a screw top. The reagents are still present. (7) HOEFFER, F.,"Histoire de 1% Chimie," Didot, Paris, 1869, 0 . 430. The symbols for the compounds in the bottles are to -~~ (8) See reference 5. be noted: the oxvaen is written as a dot over the element with which i"t%supposedly combined. This is the Co., system of Beraelius and was first put into use in 1814. We may thus date the kit as having been made some ~weig, time between 1814 and 1850, for in Booth's "EncycloSee reference 5, p. 7. pedia of Chemistry," published in 1850, this system of See reference10, p. XIII. notation had been discontinued. Seereference4, p. 48. The reagents are those used by Berzelius. They are See reference3, p. 4. calcium sulfate, iron oxide, copper sulfate, borax, lead, SMITH, E. F., J. CHEX.EDUC.,20,315 (1943). .A
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