CHAP. I. ] THE EQUIPMENT OF THE SHIP. 89 
For comparison of barometer and measures of heights, it appears that 
the aneroid barometer constructed by Goldschmid, of Ziirich, would be 
very useful. It is very desirable that the state of the barometer and 
thermometer should be read at least every two hours. 
II. Cuemicat OBSERVATIONS. 
1. Samples of sea-water should be collected for chemical analysis at 
the surface and at various depths, and in various conditions. Each 
sample should be placed in a Winchester quart glass-stoppered bottle, 
Ithe stopper being tied down with tape, and sealed in such a manner that 
the contents can not be tampered with. 
2. Portions of the same samples should be, immediately after their 
collection, boiled in vacuo, the gases collected, their volume determined 
as accurately as may be, and a portion, not less than one cubic inch, 
hermetically sealed in a glass tube, to be sent home at any time for 
complete analysis. 
3. Frequent samples of sea-water taken at the surface, and others 
taken beneath, as opportunity offers, should have determinations of chlo- 
rine made upon them at once, or as soon as convenient. 
This operation could easily be carried on in any but very heavy 
weather. On the other hand, it is not thought that any trustworthy 
analyses of gases could be made on board ship, unless in harbor or in 
the calmest weather. 
4. Such samples of the sea-bottom as are brought up should be care- 
fully dried and preserved for examination and analysis. 
5. The gas contained in the swimming-bladders of fishes caught near 
the surface and at different depths should be preserved for analysis. 
In each case the species, sex, and size, and especially the depth at which 
the fish was caught, should be stated. 
Ill. BorantcaL OBsERVATIONS. 
The duties of a botanist in traveling are twofold, and in the case of 
the voyage of circumnavigation about to be undertaken by H.MLS. 
Challenger they are of equal importance. 
Of these, the one refers to forming complete collections of the plants 
of all interesting localities, and especially of the individual islands of 
oceanic groups. 
