MEMORANDA IN REFERENCE TO THE NATURAL HISTORY OPERATIONS. 



6. Great care will be observed to place the magnets in their proper positions in the cases, 

 and not to touch them with iron or steel. The observations must be made at a distance of at 

 least 800 paces from the wagons, to avoid the influence of the iron tires. Observers will care 

 fully divest their clothing: of all substances having magnetic attraction. 



MEMORANDA IN REFERENCE TO THE NATURAL HISTORY OPERATION S. 



PREPARED BY S. F. BAIRD, UNDER THE DIRECTION OF THE SMITHSONIAN INSTITUTION. 



The general principles to be observed in making collections of natural history in a new 

 country, or one previously unexplored, is to collect everything which may present itself, from 

 time to time, subject to the convenience or practicability of transportation. The number of 

 specimens to be secured will, of course, depend upon the dimensions, and the variety of form or 

 condition caused by the different features of age, sex, or season. 



Where a small part only of the specimens collected can ^e taken along, such species should 

 be selected as are least likely to be procured in other localities or at other opportunities. Among 

 these may be mentioned the reptiles, fishes, soft insects, &c. ; in fact, all such as require alcohol 

 for their preservation. Dried specimens, as skins, can be procured with less difficulty, and are 

 likely to be brought in by persons not specially interested in scientific pursuits. 



The description of various processes,, to be employed in the collection and preservation of speci 

 mens of different kinds, will be found detailed at sufficient length in the &quot;Directions&quot; published 

 by the Smithsonian Institution, and in the Admiralty Manual of Scientific Enquiry. 



In collecting specimens of any kind, it will be important to fix, with the utmost precision, 

 the localities where found. This is especially desirable in reference to the fishes, which occupy 

 a very intimate relation to the waters in which they live. 



The smaller quadrupeds, of the size of a mouse, may be preserved entire in alcohol. Larger 

 kinds should be skinned, and the skins thrown into alcohol, or coated inside with arsenic and dried. 

 The latter course may be indicated for species larger than a prairie dog or hare. The skulls 

 of the small kinds may be left in the skins; those of the larger should be removed, taking care 

 to attach some common mark by which they may be again brought together. Large animals, 

 of the size of a wolf and above, may, for greater convenience, be skinned after the method pur 

 sued by butchers, by skinning the legs down to the toes, and cutting off at that point. The 

 skins need not be sewed up, as is directed for the smaller kinds, but rolled up into bales, after 

 applying an abundance of arsenic and drying. 



It will be very important to procure the skeletons, and, at all events, the skulls, of all the 

 species of animals, in sufficient numbers to include all the variations of age and sex. These 

 may be roughly prepared by cutting off the flesh and drying in the sun. 



As the expedition will pass through the breeding-ground of many species of birds whose nidi- 

 fication and eggs are not known, attention should be paid to securing abundant specimens of 

 the nests and eggs. As far as possible the skin of the bird to which each set of eggs may belong 

 should be secured, and have a mark attached common to it and the egg. 



The larger snakes should be skinned, as indicated in the &quot;Directions,&quot; as thereby they 

 will occupy much less space than otherwise. The smaller specimens preserve entire, together 

 with the lizards, salamanders, and small frogs. All of these that can be caught should be 

 secured and preserved. 



The head, legs, with feet, the tail, in fact the entire skin of turtles, may be preserved in 

 alcohol ; the soft parts then extracted from the shell, which is then to be washed and dried. 



Every stream, and, indeed, many localities in each stream, when passable, should be explored 

 for fishes, which are to be preserved as directed in the pamphlet. For these, as well as the 

 other alcoholic collections, the lino bags will be indispensable. 

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