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investing the prism. In size they vary from 1-25th inch, and thickness of 1-532nd inch, in the Florentine Iris, to a length of 1-1000th inch, and thickness of 1-6100th inch in the ovary coat of Centaurea nigra.

These prisms are small but distinct in the ovary coat of many Composite, as the Thistle, Knapweed, &c., but large ones occur in many exotic exogens, of which examples may be seen in the barks of Quillaya and Guaiacum. They are frequent in endogens as in the common purple Flag, and many other Iridaceæ, and often appear in the same plant with Raphides, as may be seen in certain Amaryllids; they can be well seen with polarised light.

Although the precise use of these crystals in the vegetable economy is obscure, we may conclude that whatever is constant in a plant must be important. And when we consider how commonly plant crystals are composed of phosphate or oxalate of lime, or same other compound of this earth, and its value in the growth or nutrition of animals and vegetables; and that they are plentiful in many plants which form the food of birds and mammalia, and food and medicine for man, we get a glimpse of the use of these crystals. Raphides are useful in systematic botany in distinguishing between species. We can also easily see why the gardener collects decayed leaves for his composts, and why such plants as abound most in crystals are the most valuable for the purpose. The above account has been compiled from various articles by Professor Gulliver, in the "Microscopical Journal," "The Annals of Natural History," and other scientific journals.

The weather of April last has elicited encomiums from nearly all our observers. The first ten or eleven days were cold and frosty, the night of the 1st being the minimum at nearly all stations. This frost cut off the apricots, early plums, and gooseberries, After the 10th a warm and genial period set in, which continued to the end of the month.Easterly winds prevailed, but the barometer was by no means high. Thunderstorms occurred on the 5th, 17th, 25th, and 30th. Rainfall again below the average, the only stations where maximum fall exceeded one inch being Whitfield (1-25in.) and West Malvern (1-24in.,} both on the 10th, which day produced the extreme fall at several stations in the west and in the south of England generally. In London on the 11th from 2 to 2¾ inches fell in twenty-four Lours, with a light easterly wind, but this was quite local. In the midlands generally the 20th gave the maximum fall, though this was not of very large amount. This was a very unsettled day, and marked by a change of wind from south-west to east.

As to vegetation all things look promising. The oak and elm are both leafing before the ash, giving promise {according to the proverb) of a fine summer. The apple, pear, strawberry, and the plum are making a wonderful show of blossom, and in the hedges the blackthorn has made a good show.