as extensive as has been supposed. Of the samples examined by the writer, not one of seventy-three samples from Massachusetts, not one of five from New York, and only one of twelve from Chicago, was adulterated.

The Report of the New York State Board of Health of 1882 gives one hundred and sixteen samples examined. In no case was there any intentional addition of insoluble mineral matter. Of the thirty-three powdered sugars, none were adulterated. Of the sixtyseven brown sugars, four were mixed with glucose.

The tests are not very difficult as to the presence of foreign matters, since they are insoluble in water, and half a pound of sugar dissolved in a pint of water will leave a sediment if marble or sand has been added. Tin would be detected best by the battery, a plate of copper being used as a cathode, on which tin shows very quickly. The use of sulphuretted hydrogen is not to be relied upon, since on heating there seems to be formed an organic compound of the color of tin sulphide which is very misleading.

For glucose, the test with Fehling's solution is the one most used. But here care must be taken, for, as has been said, sucrose on heating changes to invert

sugar, which reduces the copper of the solution; so that the mere fact of a slight reduction of copper does not prove wilful adulteration. For instance, in the case of candies, the writer has never yet been able to find candy or confectionery which did not reduce Fehling's solution; but it is by no means to be concluded that all confectionery is made from glucose, although undoubtedly a large part of it is so made.

Dietzsch (page 277) gives the following as a qualitative test. A dilute solution of sugar is colored skyblue with a few drops of Fehling's solution, and heated to the boiling point. If the sugar is all cane sugar, the liquid may stand twenty-four hours without showing any change; but if glucose or invert sugar is present, the reddish color of the reduced copper oxide will appear in a few minutes.

Fehling's solution may be made as follows: 34.632 grams of pure dry copper sulphate are dissolved in 500 cc. of water and put into a bottle with a glass stopper. 173 grams of Rochelle salt tartrate of sodium and ammonium and 125 grams of potassium hydrate are dissolved in 500 cc. of water, and put into a bottle with a rubber stopper. A glass stopper will be liable to become fastened in the bottle containing

caustic alkalies. The solution of copper will preserve its strength much longer if kept separate from the alkaline liquid. For use, mix the two in equal proportions, measuring the copper accurately. 50 cc. of the copper, or 100 of the mixture, are considered to reduce .5 gram of grape or of invert sugar.

The skilled analyst uses the polariscope or saccharimeter to determine the percentage of pure sugar. (See Blyth, page 120.)

A simple method of detecting starch sugar in the presence of cane sugar has been proposed by P. Casamajor. The suspected sugar is thoroughly dried, then treated with methyl-alcohol which has been saturated with starch sugar. 100 cc. of methyl-alcohol of 50° strength dissolves about 57 grams of starch sugar, and will not take up any more, but will readily dissolve cane sugar, thus taking it out of a mixture, leaving the adulterant undissolved. '

The presence of dextrine in syrups may be detected by adding an equal volume of strong alcohol to the undiluted syrup. The dextrine will be precipitated

as a white gelatinous mass.

Syrups are very liable to be not what they seem. Dr. Kedzie, of Michigan, in 1879, found only one out

of twenty-one genuine. The black color sometimes noticed when syrup is put into tea is due to the pres ence of the salts of iron derived from the pans during boiling.

HONEY.

It is reported that over 63,000,000 pounds of honey were produced in the United States in 1889, more than one-tenth of this coming from Iowa.

It is said, especially by English analysts, that much American honey is entirely artificial, the comb being made of paraffine and filled with glucose syrup. Two simple tests will show whether this is the case. Normal honey, being collected by the bees from flowers, will contain many pollen grains. The absence of these is a suspicious circumstance. Beeswax is blackened by warm sulphuric acid, while paraffine is not affected.

VI.

CANNED FRUITS AND MEATS, OR TINNED GOODS.

F an ordinary tin fruit-can is opened, and its inner

IF

surface examined, it will be found covered with the crystalline figures often produced by the action of dilute acids upon tin, and known as "moirée métallique." This apparent corrosion of the metallic surface suggests the possibility that an acid fruit, if kept for a sufficient time in such a can, may take into solution an injurious quantity of metallic impurity. Moreover, in the making and sealing of cans, a greater or less amount of solder finds its way inside, and thus the fruit comes in contact with an alloy containing from thirty to sixty per cent of lead. All the common fruits -the tomato, peach, plum, cherry, apple, pear, currant, etc. owe their acidity to the presence of acid malates, malic acid, or other organic acids.

Considerable excitement is caused every now and then by newspaper stories of the presence of tin in