The washing and getting ready for the drying oven will, in some cases, require days to carry out, if we wish to avoid losing anything. So far the proceeding is exactly the same, except draining on a filter, which would be adopted for preparing for the microscope. On no account should the opportunity be missed of mounting several slides permanently for microscopic examination. Drawings or photographic enlargements will render us independent of direct microscopic appeal, which is not at all times convenient. The substance, if drained and allowed to dry on the filter, will adhere most tenaciously to it, so that it is better to complete the drying in a porcelain or platinum capsule, either by swilling the filter with a jet of water or by carefully removing with a spatula. The most strenuous care must be used not to contaminate the specimen with loose fibers from the filter. The perfectly dried matter is best treated in exactly the same way as a residuum in water analysis. It is a common thing to ignite the residuum, and to put the loss down, if any, to water. This ought not to satisfy an accurate observer, since organic matter, carbonates--especially in presence of silica--will easily add to the loss. The best plan is to heat a small portion very cautiously, and note if any smell or alteration in color, due to carbon, etc., is perceptible, and to proceed accordingly. I have seen some very satisfactory analyses made on board ship by a skillful use of the blowpipe, where liquid reagents would be very inconvenient to employ. It will be necessary to say a few words as to the way in which soundings are made at sea. When the bottom consists of sand, mud, or other loose matter, it is easy enough to bring specimens to the surface, and, of course, we know in such a case that the bottom has been reached, but, in the event of the bottom being hard and rocky, it is not easy to say that our sounding has been successful: and here we meet with a difficulty which unfortunately is most unsatisfactorily provided for. The lead is "cast," as the saying goes, "armed" for this emergency. An iron sinker is made with a hollow recess in the bottom; this is filled in with tallow, and on striking the bottom any loose matter may adhere by being pressed into the tallow. If the bottom is rocky or hard we get simply an imprint in the arming, and when such a result is obtained the usual construction is that "the bottom is rocky" or hard.