122 THE AMERICAN MONTHLY [May, 



were then on their way to the river to spear sahiion, some of 

 them having come a long distance for the pnrpose. 



Cedar Trees and Apple Rust. — Prof. B. D. Halsted gives 

 some interesting facts regarding tlie apple rust {Rcestelia) that 

 yellows the foliage of the orchard in July and shortens the crop 

 at picking time. He says : " This fungus plays a double role and 

 seems unable to get along with the apple tree alone. In a second 

 and very different form, Gy^mio-sforaiigium ^ it infests the cedar 

 trees, there forming knots or galls that become conspicuous as 

 gelatinous balls during the spring rains. These orange-colored 

 balls furnish the spores, which, falling upon the foliage and fruit 

 of the apple tree, produce that fatal rust. Later in the season the 

 spores from the apple fungus go back upon tjie wings of the 

 wind to the cedar and a new crop of galls is obtained for next 

 spring's campaign against the orchard. In this case it is not wild 

 apple trees or those of the same family that harbor the enemy, 

 but a tree as widely separated botanically from the apple as is 

 well possible. More than this, the fungus changes its form in 

 passing from one to the other so that it was not until demonstrated 

 by actual cultures that the relation, long suspected, could be fully 

 believed. It is needless to say that the very evident method of 

 procedure is to destroy cedar trees that are anywhere near the ap- 

 ple orchard. A single large gall-bearing cedar tree just outside 

 the orchard fence may do more mischief than any enemy that is 

 lurking within the enclosure." 



Arbor Day. — By proclamation of the Governor, April 28 was 

 observed in Michigan as Arbor Day. He appealed to all the 

 people to plant trees along the highways and about their homes, 

 so that flowers, shrubbery, and fruit trees may add to the happi- 

 ness of every passer-by. 



DIATOMS. 



To >A^ork the Diatomaceous Earth Sent out by This 

 JournaL — i. Boil the material in clear filtered water, let it cool 

 and settle. Carefully pour away the surplus water, add fresh, 

 and boil again. Repeat this boiling and washing until the water 

 remains clear ; finally decant the water, leaving the diatoms as 

 dry as possible. 



2. Add half a drachm of strong nitric acid, boil thoroughly, 

 drop a small crystal of bichromate of potash into the hot acid, 

 boil again for several minutes. Add clean water and allow it to 

 settle ; pour away this acid water, add fresh, and repeat this wash- 

 ing until the water remains clear and neutral. 



3. Add a piece of clean soap, about the size of a pea, and a lit- 

 tle water to the diatoms, boil thoroughly, add fresh water, and 

 allow plenty of time for the smaller diatoms to sink through this 



