[Illustration: TAPPING THE GROVE.] When the sugar maker has finished tapping his trees he is ready for a flow of sap. Sometimes it comes at once and then again the weather may turn suddenly cold and for a week or ten days there is nothing doing in the sugar camp; meantime he can get his boiling apparatus in readiness and perhaps get a little more wood. But spring will come sooner or later and there is bound to be a rush of sap. Then comes the busy time in the camp; the men and boys gather the sap with oxen and horses. This is usually done with a tank holding from 20 to 40 pails on a sled and drawn to the sugar house and stored in tanks from which in turn it flows to the boiling pan or evaporator; the flow from the storage tank being regulated by feeders which keeps the boiling sap in the evaporator constantly at the same level. The sap as it boils passes from one compartment to another becoming more dense and sweeter until it reaches the syruping off pan, where it is drawn off in the form of syrup. The right density can be determined by a thermometer or the skilled operator can tell by the way the syrup “leather aprons” from the edge of the dipper. If the thermometer is used a temperature of 219° F. will give a syrup that will weigh eleven pounds to the gallon net. It must be remembered, however, that the thermometers are graduated at the sea level, and as the altitude increases a lower temperature will give the same result on account of the reduced air pressure. An allowance of 1° for every 500 feet rise has been found to be about right; thus at an altitude of 1,000 feet a boiling temperature of 217°F. will give the 11 pounds syrup. Syrup is not however usually brought to the required density in the evaporating pan but is drawn off a little less than 11 pounds net, and brought to a uniform standard in larger quantities than would be possible in the evaporating pan. The fire under the boiling sap should be quick and hot, as the sooner it is reduced to syrup after it runs from the tree the better the product. As the sap begins to boil a scum of bubbles rises to the top, which must be constantly removed with a skimmer, and the man who tends the fires, skims the sap and draws off the syrup has a busy job. When the sap has been reduced to syrup having a density of about 11 pounds to the gallon, the niter or malate of lime, sometimes called sugar sand, which is held in solution in the sap and which crystalizes or precipitates at this stage of evaporation, can be separated from the syrup. This is accomplished in two or more ways; some strain it through felt while hot and leave the syrup free of niter; others let stand in buckets or tanks until cold; then turn or draw off the clear amber syrup leaving the malate of lime at the bottom.