If the adulteration of guano has been made by sand, it can be detected by dissolving the ashes in muriatic acid. The sand will remain--if it is more than one per cent., it has probably been added fraudulently. As iron exists in loam, it will show in the color of the ash if that is the substance used for adulteration. If lime has been added, it can be detected by dissolving the ash in muriatic acid and separating the sand, loam and iron, if present, by filtration, and then adding oxalate of ammonia to the liquid. If it shows more than a mere trace of lime, it has been falsified. _Test by salt._--Saturate a quart of water and strain it; pour some in a saucer and sprinkle guano upon the surface. Good guano sinks immediately, leaving only a slight scum. If it has been adulterated by any light or flocculent matters, they will be seen upon the surface of the brine. _Test by Acid._--Put a teaspoonful of guano in a wine glass and add a little vinegar or dilute muriatic acid. If ground limestone or chalk have been added, the effervessence will show it. A genuine article will only show a few bubbles. _Test by Water._--The following simple plan will easily detect all the ordinary adulterations of guano. Procure a wide mouthed bottle, with solid glass stopper; fill with water and insert the stopper; let the exterior be well dried. In one pan of accurate scales, place the bottle; counterpoise by shot, sand or gravel. Pour out two thirds of the water, and put in four ounces avoirdupois of guano. Agitate the bottle, add more water; let it rest a couple of minutes, and fill with water, so the froth all escapes; insert the stopper, wipe dry, and replace the bottle in the scale. Add now to the counterpoised scale, one and a half ounces avoirdupois, and a fourpenny piece; if the bottle prove the heavier, the guano is, in all probability, adulterated. Add in addition a three-penny piece, and if the bottle is still heaviest the guano is undoubtedly adulterated. By this simple experiment, a very small amount of sand, marl, &c., is detected. If farmers will not use some of these simple tests, or employ a chemist to detect suspected adulteration; or if they will buy guano of men who have no character to lose, and who offer to sell below a price to afford them a living profit, they cannot be pitied if they are cheated. _Prepared Guano._--Never buy anything bearing that name, unless you wish to verify the adage of "the fool and his money are soon parted."