If other varieties contain a larger proportion of phosphates, and are sold at a less price, experience proves they are not cheaper. If an additional quantity of phosphates is desirable, it can be obtained in a cheaper form from dissolved bones, or bone dust and shavings of bone workers; or from mineral phosphates of lime. Recollect, guano under no other name, has ever equalled the Peruvian, in the results as compared with the quality or cost. Therefore buy none but Peruvian. To guard against deception, be careful of whom you buy. If you cannot buy directly from the agents, be sure the character of your merchant is a sufficient guarantee against adulteration. _To test the quality of Guano._--The best test is the price. Unlike other merchandise, this article is not subject to fluctuations. Being a government monopoly, the price at which the agents are to sell here is fixed in Peru, and that price may be easily known; therefore, if any dealer offers you Peruvian guano at "a reduced price," you may be sure the quality is reduced also. Remember, that the lowest price by the ship load, it can be procured for of the agents in Baltimore or New York is $46 per ton of 2240 lbs. To this, every fair, honest dealer, must add freight, insurance and profit. Every man who sells without such addition, you may be sure will make his profit by short weight or adulteration. The next best test is its appearance. Good Peruvian guano is an impalpable powder, perfectly dry to the touch, of a uniform brownish yellow color, with a strong smell, like that of spirits of hartshorn, contained in ammoniacal smelling bottles. But the smell is no test; that which smells strongest may be worst, as the ammonia may be disengaged by moisture or by the addition of lime or salt.