CHEMICAL NEWS, { Report of Chemist, Department of Agriculture, USA. Jan. 26, 1917 reaction periods and a very low activity during the rest. The more dilute nitric acid used in Experiment 10 produced high passivity during the first reaction period, but the later constants showed no more passivity than might be expected, according to the results of Experiments 6, 7, and 8, from the action of the chromic acid alone. For Experiments II and 12 the sulphuric acid concentration was increased to 5 molar with very beneficial results. The absence of any indication of passivity in these experiments seems to prove that this concentration of sulphuric acid was sufficient to entirely overcome the tendency of chromic acid to produce passivity in the nickel discs. The rate of the reaction shows a satisfactory constancy, and the mean value of the velocity constant agrees with the values obtained with several other metals under like conditions. Tin. The study of tin in chromic acid solution was confined to the two experiments numbered 13 and 14 in the table, both conducted in the presence of 5 molar sulphuric acid. The results are in both cases apparently normal, and the reaction velocity has the expected value. This behaviour on the part of a metal-forming soluble and stable salts of two different valencies indicates one of two possibilites; either (a) the second stage of the oxidation does not occur to a measurable extent (the case observed with tin in ferric sulphate), or, (b) the second stage is so rapid that no appreciable diffusion of stannous salt away from the metal can occur. As the reaction between stannous sulphate and chromic acid is practically in. stantaneous there can be little doubt that explanation (b) is the correct one here. Silver-Experiments with silver in chromic acid gave the values recorded in Nos. 15-19 of Table X. In general, the results resemble those given by silver in ferric sulphate, both in the relatively low reaction velocities observed and in the fact that the velocity tends to decrease as the silver salt accumulates in the solution. On account of this decrease the reaction velocity characteristic of a given experiment is best represented, as in a number of cases already considered, by the "initial velocity," found by extrapolating back to time zero. To be continued). REPORT OF THE CHEMIST, DEPARTMENT OF AGRICULTURE, BUREAU OF CHEMISTRY, WASHINGTON, D.C., U.S.A. (Concluded from p. 33). Enforcement of Food and Drugs Act. Domestic Foods and Drugs.-Five hundred and seventyseven recommendations for seizure and 787 recommendations for criminal prosecution were made through the office of the Solicitor to the Department of Justice. The work with the Bureau of Standards to establish "tolerances and reasonable variations" under the net-weight ameudment has progressed, that upon dairy products being com. pleted. Among the 1036 cases of all kinds terminated in the courts during the year were 198 alleging false and fraudulent labelling of medicines, in all of which save five the courts found for the Government. In one food case a sentence of imprisonment was imposed. A number of indictments for conspiracy were found, upon evidence obtained by the bureau, concerning the adulteration of olive oil, domestic traffic in refuse eggs, traffic in refuse eggs exported to England, and the sale of spurious synthetic drugs. There were collected 4483 official samples. These showed an increasing percentage of substantial v olations, an index not of increased disregard of the law, but, as pointed out in the report last year, solely of greater discrimination in the selection of samples. In addition an increased number of informal samples, about 4000, were 43 taken, because these demand less labour and yet are adequate for the routine checking of staple products to gauge the effect of the bureau's action, and for general surveys preliminary to definite campaigns. The number of official samples analysed by the field force is given in Table I. The use of the guaranty legend and serial number ceased very largely during the year. In the Service and Regulatory Announcements were published 52 opinions and 600 notices of judgment. All the work on the certification of colours was concentrated in Washington. The laboratory at New York City was transferred to new and more commodious quarters in the United States Appraiser's Stores. The St. Paul laboratory was moved into the new Federal building in Minneapolis. The dairy laboratory was abolished and its work distributed among other laboratories of the bureau. A separate office has been established to deal with cases of false and fraudulent labelling of medicines and mineral waters under the Sherley amendment to the food and drugs act. To this office are also referred such medical matters as may arise in connection with the work of the bureau. At the request of the Secretary an officer of the United States Public Health Service was detailed to take charge. In consequence this work has been carried on more expeditiously and efficiently than heretofore. A very close inspection was maintained during the past year over the early shipments of oranges and grapefruit. In this campaign the bureau received the active help of the greater part of the citrus fruits producers. Comparatively few sweated, immature oranges or grapefruit were marketed. The better quality of the fruit is believed to have resulted in a steadier market, so that the producer as well as the consumer benefited. The unusual demand for cotton lint by the munitions factories greatly increased the delinting of cotton seed. The cake and meal made from such delinted seed bas usually less protein than that from undelinted seed. Many mills in labelling their product used the analyses of former years, thus misleading the consumer, who, as a rule, was unable to protect himself because of the rising market. With the assistance of State officials, the Bureau has taken action in many cases. Based upon co-operative sanitary surveys of the waters over oyster beds in certain sections, described in the report for the last two years, the department, by appropriate notice, warned the producers against the shipment interstate of oysters from such sections during the fall, spring, and summer, when the oysters are not hibernating. In the case of particular regions warning of this nature had been issued some few seasons pior to last year. This warning had not been heeded in all cases. Last fall prosecutions were brought, with the result that all shipments from such condemned territory thereafter were stopped in the fall and spring. Other forms of adulteration not already mentioned that received special attention are: The substitution of mountain maple, Acer spicatum, for cramp bark, Viburnum opulus, the adulteration of oysters, scallops, and canned tomatoes with water, the substitution of coloured starch paste for tomato sauce, the reprocessing of spoiled canned goods, the traffic in cull beans, in decomposed tomato products, in rancid olive oil, in wormy horse beans, the substitution of foreign fat for cacao butter in, and the addition of cacao shells to, cacao products, the adultera. tion of rice bran with rice hulls, the colouring of inferior macaroni and of plain noodles, the misbranding of domestic macaroni in simulation of imported goods, and the adulteration of oats with water or weed seeds. Co-operation with State Officials.-It is not possible to give a complete account of the assistance given State and municipal officials by the Bureau, or of the assistance received by the Bureau from them, because much of this co-operation is of an informal nature and because local officials do not always report to the Bureau upon the value of the information received. However, such co-operation TABLE 1.-Report of Branch Laboratories for year ended June 30, 1916. Import samples, analyses. NEWS Hearings held. Interstate samples, analyses. Miscel- Total laneous samples samples. analysed. By Personal. correspondence. Central district has been more effective than ever before owing to the manner in which the Office of State Co-operative Food and Drug Control, established in 1914, has conducted its work, described in a general way in the report of last year, and because of the greater amount of information it has distributed. Many conferences have been held with State officials, and they have been notified of the beginning and termination of court cases, of court decisions, of all public hearings held by the Bureau. Twenty-three sets of information cards on methods of food and drug analysis have been issued to them and they have been furnished copies of analyses and inspection reports. A Manual of Procedure for the Guidance of State Health, Food, and Drug Officials has been compiled and forwarded to State officials for their information and guidance when endeavouring to use the Federal food and drugs act as outlined in Section 5 of the act. A list of Federal and State Daity, Food, Drug, and Feeding Stuffs Officials has been prepared and kept up to date for the information of these officials. A compilation of State food and drug laws and of State food inspection decisions has been begun. Twenty-three instances of seizure action instituted by State officials are known to the Bureau. Other seizure actions under the Federal law, not reported to the Bureau, were undoubtedly inaugurated by joint action of the State official and the local United States attorneys. One hundred and ninety-one official samples were collected by State officials in 19 States. Among the adulterated articles proceeded against under State laws or municipal ordinances upon information furnished by the Bureau may be mentioned decomposed eggs, decomposed canned goods, decomposed fish and poultry, polluted or watered oysters, watered scallops, saponin-containing foods, iquors containing wood alcohol, mi-branded nostrums, and spurious drugs. In a large number of instances information was given to the Health Department of New York City which led to condemnation of adulterated food not coming under the jurisdiction of the Federal act. Many of the State and municipal officials have reciprocated for information of this kind by furnishing to the Bureau evidence of violations of the Federal law. Among the most notable instances are polluted or watered oysters, watered scallops, adulterated milk or cream, decayed eggs, decomposed canned goods, butter, and fish, wood alcohol in liquors, cottonseed meals and other feeds below guarantee, adulterated oats, and misbranded nostrums. Some specific instances of effective co-operation with State and municipal officials have been mentioned above in connection with other phases of the Bureau's work. Two other types follow: Abnormal trade conditions fostered the production of spurious drugs in place of synthetic ones which are ordi narily imported, notably acetyl-salicylic acid and neosalvarsan. Though a number of shipments were seized, a number of individuals successfully prosecuted under the food and drugs act, and indictments returned under the postal laws, the traffic could not wholly be suppressed by Federal action nor the goods in the hands of local dealers in many sections of the country destroyed. The situa tion was laid before State and municipal officials, who instituted many prosecutions and seizures with the result that through this joint action this fraudulent traffic was broken up. In co-operation with the food and drug commissioner of Texas, the cause of contamination of certain wells in Texas, the water of which is widely distributed, was determined. When the results were laid before the local authorities steps were taken to remedy the situation. Similar action has been taken in the case of other spas. The co-operation iu the sanitary control of the milk supply of small cities described in the report for last year has been extended in Illinois, Iowa, Missouri, Kansas, Nebraska, and in New England. It is proposed to repeat this work year after year, extending it each year to new territory. In some localities bad conditions were found, due in the main to insufficient cooling and careless handling. Perhaps the best result of this work has been that it stimulated some of the local authorities to take up similar work independently so that definite permanent im provement of the milk supply of a number of cities has CHEMICAL NEWS, Jan 26, 1917 resulted. The co-operative work on the control of the shipment of decomposed eggs described in the report of last year has been extended to cover much of the territory in which shipments originate, so that eggs are now candled before shipment far more than formerly and the spoiled eggs destroyed or fed to poultry and stock. At the same time information given to local officials has helped them to curb local traffic in eggs rejected in candling. Do Equiatomic Solutions in Iron possess Equal Resistances? The joint committee on definitions and standards has considered a large number of products. Based upon its recommendations the following food inspection decisions have been issued: No. 160, Gluten Products and "Diabetic" Food; No. 161, Maple Products; No. 162, Egg Noodles and Plain Noodies; No. 165, Cacao Products. Importations.-The analyses and inspections made in the control of the importation of foods and drugs have been tabulated in Table I. Owing to the unusual trade conditions, while the quantity of imports has been reduced, the variety has not; and there has been such a variation in a single class of products that it has been found necessary to make a great many more examinations of a single importation than were formerly required. This situation is particularly reflected in the quality of the crude drugs and spices received. Prices have been unusually high and the temptation to offer spurious or adulterated articles correspondingly great. The quality of senna leaves, cin chona products, ipecac, and strophantus was often poor and sometimes a completely spurious article has been offered. The inability to procure certain spices from the usual sources has resulted in the introduction from new sources of new types. some of which were adulterated or spurious. Especial difficulty was encountered with coriander, fennel, celery, anise, cumin, and Chinese and Indian mustard. The poisonous leaves of Coriaria myrti folia were found in marjoram leaves, Origanum marjorana. Owing to the increase of the Bureau force of microscopists the control of crude drugs and spices is becoming more effective. Worthy of special mention is the continuation of the exclusion from New England of spoiled Canadian milk and cream. Especial attention has also been paid to decomposed tomato products, spoiled sardines, and wormy olives. Mineral waters have been frequently examined for pollution. Many misbranded medicines have been detained until the misbranding was corrected. Many shipments of low-grade alimentary pastes coloured in simulation of high grade products have been excluded. Collaboration. For other bureaus of the department 8194 samples were analysed. For other executive departments and Government establishments 789 were analysed as shown in detail in Table II. The totals do not include samples that were analysed by the field service of the Bureau. These are included among the miscellaneous samples given in Table I. 45 Department. Assistance was also rendered at hearings and in court at trials. Assistance was also given in the revision of the United States Pharmac poeia and in the revision of the official methods of analysis of the Association of Official Agri. cultural Chemists. DO EQUIATOMIC SOLUTIONS IN IRON THE Conception that carburised iron or steel is to be regarded as a solidified solution dates back as far as Proust in 1806, but the idea apparently remained dormant until 1863, wheh it was again suggested by Mathiessen. Since this latter date it has been more or less accepted by an increasing number of metallurgists and chemists, until at the present time it is almost universally acknowledged as being the most satisfactory theory to account for the properties of metals. That some intimate relation exists between the chemical composition of steel or other alloys and their electrical resistance was clearly pointed out in 1863 also by Mathiessen, and since that time the examination of this phenomenon has been the basis of many researches, such as those carried on by Johnson, Hopkinson, Osmond, Stead, Ebeling, Mathews, Hadfield, Benedicks, and Portevin. In 1898 Le Chatelier, in an article on the electrical resistance of steel (Comptes Kendus, 1898, cxxvi., 1709, 1782), drew four conclusions as the results of his investigations: 1. The resistance increases with the percentage of carbon in the case of annealed steels. 2. For every 100 atoms of an alloy one atom of silicon increases the resistance by 7 microhms; one atom of manganese increases the resistance by 5 microhms, and one atom of nickel by 3 to 5 microhms. 3. Chromium, tungsten, and molybdenum have but slight influence on the resistance. 4. One atom of hardening carbon produces an increase in the resistance, practically equal to that of silicon. Although Le Chatelier's work indicated that equiatomic concentrations of carbon as hardening carbon and silicon exerted practically equal effect on the specific resistance, while that due to manganese was only about five-sevenths as great, that of nickel three-sevenths to five-sevenths as great, and that due to chromium, tungsten, and molybdenum was very slight, Benedicks, in 1902 (Zeit. Phys. Chem., 1902, xl., 545), from the results of measurements made on seven steels in both the hardened and annealed condition, laid down the general law that equiatomic solid solutions in iron possess equal resistances. The formula which Benedicks proposed as the result of the study of his data was :-p = 7 6+26·8 ΣC microhnis cc.; in which p is the electrical resistance of the steel, 7.6 the TABLE II.-Miscellaneous Analyses for other Branches of electrical resistance of pure iron, and ΣC is the sum of the values in terms of carbon of the elements dissolved in the iron. The "carbon value" is obtained by dividing the percentage found on chemical analysis by the atomic weight of the element and multiplying the result by 12, the atomic weight of carbon. No claim is made by Benedicks that the general law holds if the total carbon value exceeds 2 or at the outside 3 per cent. In an exhaustive study of the "General Considerations regarding the Electrical Resistance of Steels (Iron and Steel Institute, Carnegie Scholarship Memoirs, 1909, 1., 383). Portevin makes the following statement in regard to Benedicks' formula : "An attempt was made to verify this formula in the case of the steels which were employed for the shearing tests, the analyses of which have already been given in the first part of this report. The results of the calcula. * A Paper read before the Faraday Society, December 18, 1916. 46 Do Equiatomic Solutions in Iron possess Equal Resistances? tions are not recorded for the steels with low percentages of the special elements. Sometimes they agreed with the law, and at others the results were very far removed from the calculated resistances." In order to develop a formula which would give calculated results in close agreement with those obtained experimentally, it was necessary for Benedicks to make two assumptions:-First, that the specific resistance of the pure iron solvent was 7.6 microhms, and, second, that steels with more than o'45 per cent carbon retained o 27 per cent in solid solution even when annealed, but that steels containing less than 0:45 per cent retained only between 0.06 and o'07 per cent in solution after slow cooling. The carefully conducted experiments carried on during the past twenty years by J. O. Arnold, in which from 95 per cent to the entire amount of carbon in annealed steels has been recovered in the form of precipitated carbides, which tend to disprove the assumption that steels containing more than 0.45 per cent would retain o 27 per cent carbon in solid solution. The principal object of the experimental werk herein described, which was carried on by Walter E. Jominy, M.Sc., has been to see whether it might not be possible to suggest a more satisfactory hypothesis to explain the relation existing between the carbon concentration and specific resistance of heat-treated steels than is offered by Benedicks' law. The seven steels, which were furnished through the courtesy of the Pennsylvania, the Halcomb, and the Carpenter Steel Companies, consisted of one very pure basic open-hearth steel, three hypoeutectoid steels, and three which did not differ much from the eutectoid composition, one being somewhat below and the highest somewhat above the eutectoid point. The complete analyses of these steels, together with the carbon value of elements other than carbon, and the total carbon value, EC, are given in Table I. Bars of the above steels, a little more than 6 mm. square and 15 cm. in length, were suspended in an electrically heated furnace, so arranged that the temperature could be accurately measured by means of a platinum rhodium thermo-element, and oxidation of the bars during the time they were in the furnace could be completely avoided. When the furnace had been brought to the temperature from which it was desired to quench the bars, these latter were put in the furnace and allowed to remain one hour, in order to attain the exact temperature indicated by the thermo-element, which was placed within 2 or 3 mm. of the steels. The first four steels were quenched from 908° C. and the last three from 903° C. The time, taken with a stop-watch, required to transfer a bar from a furnace to a large body of ice-water used as quenching bath averaged about one second; while that required by the bar to cool below red-heat was from four-fiths of a second to one second. From five to six seconds were required to cool the bar to the temperature of the bath. After being hardened in this way the bars were polished, and the specific resistance was determined, the measurements being made on each bar immersed in an oil-bath maintained at 25° C. The specific resistances were determined by measuring the fall in potential between knife edges clamped to the bar 10 cm. apart, while a current of constant density was flowing through the bar. The fall of potential was com pared with that given by a standard resistance which had been calibrated by means of a Siemens and Halske potentiometer and a certified standard cell. Measurements could be easily duplicated to within less than 0.05 microhms. and it is thought that the values given do not differ more than o'a of a microhm from their absolute value. After measurements of the specific resistance of the quenched bars had been made, the bars were placed in a drying oven maintained at a temperature of about 105 C. for two days. This enabled the measurements, which were made at 95° C., to be made without appreciable change during the time of measurement. The bars were CHEMICAL NEWS, { Jan. 26, 1917 finally carefully annealed by heating up to 880° C. and allowing to cool very slowly in the furnace over night. The specific resistances of the bars in both the hardened and annealed conditions, together with the theoretical values calculated from Benedicks' formula, and the deviations of the value actually determined from those calculated, are given in Table II. In this same table the next to the last column shows the drop in the specific resistance due to the precipitation of carbides produced by annealing; while the last column gives the theoretical change in specific resistance which would be produced by the precipitation of 1 per cent of carbon, assuming the precipitation to be complete. If the molecular weight of the carbides decreases as the per cent of carbon increases, as was shown to be the case from a study of the products of solution of steel in 1899 (Fourn. Iron and Steel Inst., lvi., 223), since the carbides of low molecular weight are more readily soluble than those of high molecular weight, the progressive increase of effect on specific resistance for unit concentration of carbon with increasing carbon content of the steel, as shown in the last column of Table II., would be even more accentuated than the figures show. For purposes of studying, the steels given in Table II. can be best divided into two groups of three each, beside the one steel, CO; the first, or hypoeutectoid, group consisting of H35. H41, and H57; and the second, or eutectoid group, consisting of C4, C5, and C. The marked deviations of the values found from those calculated from Benedicks' formula may be considered as follows:: For steel CO, the formula gives a value of 9.63 microhms, a figure probably lower than that which has been obtained experimentally from the purest iron ever measured. The calculated values for H35 and H41 annealed are also lower than those experimentally found, since in these two cases the assumption is made that 0:07 per cent of carbon remains in solid solution, but the specific resistance due to this amount would not be sufficient to offset the low specific resistance, 7 6 microhms, assumed to be that of pure iron. According to Benedicks' formula o 27 per cent of carbon would be equivalent to 7°24 microhms, and the further assumption is made that in annealed steels all those containg more than o'45 per cent carbon retain o 27 per cent in solid solution. The 7.24 microhms, due to the assumed o 27 per cent carbon remaining in solid solution, would more than offset the low specific resistance assumed for pure iron; and, in consequence, we find the calculated value for H57 annealed 2.94 microhms higher than that actually found by experiment. This deviation from the calculated value decreases with increasing per cent of carbon, as might be expected, since, as has been pointed out before, the mean molecular weight of the carbides decreases as the per cent of carbon increases; and since the carbides of low molecular weight are more readily soluble than those of high molecular weight, the amount retained in solid solution in annealed metal would be reasonably expected to increase with increasing per cent of carbon, so that by the time the steel C is reached, the observed value at proaches quite near that calculated. In the case of the hardened steels the calculated specific resistances are too high in the hypoeutectoid group, the deviation increasing from H35 to H57. In the eutectoid group the calculated values approach much more nearly those found experimentally. The calculated value of C4 is only o 80 microhm too high, while the values of C, and Cy are both below those found by calculation. All the deviations of the hardened steels cannot be satisfactorily explained by any hypothesis which assumes that equiatomic concentrations of carbon produce equal effect on the specific resistance. In the eutectoid group, in going from C4 to C2, it will be noted that an increase of o 29 per cent of carbon has produced an increase of 9.12 microhms in the total specific resistance. This figure, calculated to a basis of one atom of carbon to 100 of the alloy, would give a value of 673 microhms, which is in very satisfactory agreement with CHEMICAL NEWS, Jan. 26, 1917 Carbon Do Equiatomic Solutions in Iron possess Equal Resistances? 47 H35 H41 H57 0.108 0.678 C4 0.76 0167 that of practically 7 microhms given hy Le Chatelier as the value of one atom of hardening carbon in 100 of alloy. The value 6 73 microhms was obtained from steels quenched from 903° C., but experiments carried on in this laboratory have shown that if the quenching temperature had approached 1100° C., this value would have exceeded 8 microhms, on account of the lowering of the molecular weight of the dissolved carbides with the increased temperature. On the other hand, in the hypoeutectoid group, in going from H35 to H57, it will be noted that an increase of o 22 per cent carbon has produced an increase of 3.78 microhms in the total specific resistance. This figure, calculated to a basis of one atom of carbon to 100 of the alloy, would give a value of 3.68 r icrohms, which is not much more than one-half of the value obtained by an equal atomic concentration of carbon in the form of the carbides found in the eutectoid steels. The values 6.73 and 3 68 microhms, for two equiatomic concentrations of carbon but in different groups of steels, show very clearly that some other explanation than |