The San Francisco call., 1898-01-02
- HE latest and, perhaps, one of
 the most useful applications of
 the x ray is the examining of
food preparations for the pur


 food preparations for the pur-
 pose of ascertaining the presence of adulteration.
 Experiments having this end in view have recently been made by Miss Fleischman at herlaboratory on Sutter street and the results have been satis- factory in the highest degree.
 In the scope of her experiments Miss Fleischman has covered nearly all the manufactured food products on the market and the presence of foreign substances has in every instance been detected. With the staple articles of food, such as tea, coffee, sugar, flour and baking powder the X-ray pictures are: very strong and only a glance is . neoessary to detect the presence of for .. eigp matter, although to the eye the ~ articles. themselves appear perfectly pure..
 In making these examinations Miss Fleischman proceeded in exactly the same manner as in making radiographs of different parts of the human body The articles to be examined were plac- ed on top of a sensitive plate and given a brief eXposure to the x rays. The plate was then developed and the print from it showed all the differentiation of the objects photographed.
 From what is known of the action of the X ray there is no reason why this should be otherwise. Most food Dre- parations capable of being adulterated are: of a vegetable nature, The adul- teTatiQns used are in most instances of 3 mineral nature. As is already we'll Known, vegetable substances offer scarcely any resistance to the x rays while minerals oppose them most for : cibly.
 .,:. Fr0m this it must follow that when % the two, composed of thousands of small particles, are mixed and both =glVen the same exposure to the x ray the result will be that the plate is af 1ecCted more in some places than in others: In the finished pictures there -"lil De perfect impression of the min . efaf substances, while the vegeta ble 7 substances can scarcely be seen. - ms IS most apparent in the radio graphs ef Hour. A teaspoonful of pure Hour put on a sensitive plate and spread out to thickness of not more * than. sl' sixteenth of an inch after 2 short exposure to the rays. will yield an almost imperceptible image. The rpunding of the different lumps of f,our will show as light tone spread over a white surface. But let there he so much. as one grain of sand in the spoonful of flour and it will stand out inlSy black with startling distinctness. If: there are a hundred grains they will shoW:tas a hundred round, black dots. ;%I$(lt suppose the flour is adulterated with white clay, starch or chalk In that case. each will yield different inn : pnessioh. The clay will appear as jag ged. spots, not :so dark as the spots made by sand. The starch will show as a crystal formation very little dark CT than the flour itself and the chalk will show as Iarge, round Jumps almost as dark as the clay.
 n It. makes no difference whether the Manifestations are present .singIy or in combination, all will show, and in al- most exact proportion. Sand, clay, starch and chalk in equal proportions, mixed with certain quantity of flour, will all show distinctly ip a radio graph. To be sure there will be jum-