CANADA BALSAM FOR MICROSCOPY
Due to its high optical quality, its refractive index (n = 1.55, very close to that of glass), and its purity it is mainly used in optics as an invisible-when-dry glue for glass. Some use include in microscopy to conserve microscopic samples. The sample is sandwiched between a microscope slide and a coverslip and Canada balsam is used to glue the arrangement together and enclose the sample to conserve it.