. Molkerei Chemie; ein praktisches Handbuch für Molkerei Chemiker und andere die Kontrolle über die Molkereien. Landwirtschaftliche chemie; Milch. 340 BUTTER. viel Schwierigkeit in distinguisting dieses aufgrund seiner großen refrac- tive macht. Die Folie sollte verschoben werden, um zu prüfen, alle Teile, wie in den Fällen, in kleiner Mengen von Verfälschungen, die Margarine ist nicht gleichmäßig, und zwei oder mehr Teile aus verschiedenen Teilen der Probe verteilt kann geprüft werden. Als check, natriumselenit Platte (eine kristalline Form von Calciumsulfat, die Eigentum der Rotatorischen Dispersion zu einem großen Teil besitzt) ist ne

• Bildanbieter: The Book Worm / Alamy Stock Foto
• Bild-ID: RDYW83
• Dateigröße: 7,2 MB (431,4 KB Komprimierter Download)
• Freigaben (Releases): Model - nein | Eigentum - nein
• Format: 1554 x 1609 px | 26,3 x 27,2 cm | 10,4 x 10,7 inches | 150dpi

Weitere Informationen

Dieses Bild ist ein gemeinfreies Bild. Dies bedeutet, dass entweder das Urheberrecht dafür abgelaufen ist oder der Inhaber des Bildes auf sein Urheberrecht verzichtet hat. Alamy berechnet Ihnen eine Gebühr für den Zugriff auf die hochauflösende Kopie des Bildes.

Dieses Bild kann kleinere Mängel aufweisen, da es sich um ein historisches Bild oder ein Reportagebild handel

. Dairy chemistry; a practical handbook for dairy chemists and others having control of dairies. Agricultural chemistry; Milk. 340 BUTTER. much difficulty in distinguisting this owing to its great refrac- tive power. The slide should be moved about to examine all parts of it, as, in cases of small amounts of adulteration, the margarine is not equally distributed throughout, and two or more portions from different parts of the sample may be examined. As a check, a selenite plate (a crystalline form of calcium sulphate, which possesses the property of rotatory dispersion to a large extent) is next placed under the slide, the microscope focussed, and the sample again examined. In this case the slide will be uniformly illuminated when the prisms are crossed, but will appear coloured ; the colour depends on the thickness of the selenite and the position of the Nicol prisms, but when pure butter is examined the whole of the field appears of one colour. When margarine is under observation certain parts of the field are seen to be of a different colour.. This modification is, when used by persons of absolutely normal vision, quite as delicate as the examination without selenite, but it cannot be generally recommended, as the per- ception of colour is a sense in which many people—more than is commonly supposed—are somewhat deficient, though not abso- lutely colour blind. The usual colours which selenite plates are constructed to give—red and green—are those which are least easily distinguished by the majority of those who suffer from weak colour perception. It is advisable, therefore, never to omit the examination without a selenite plate. It is, of course, essential to employ a good microscope, as any illumination of the slide, except by light which has passed through the polariser, will prevent the extinction of the field on crossing the Nicol prisms. Though it is impossible in practice. Please note that these images are extracted from scanned page images that may

Stockbilder mithilfe von Tags suchen

• bookcentury1900
• bookdecade1910