31 
of Edinburgh, Session 1884-85. 
stop the vessel more frequently than necessary, and surface samples 
are usually collected by means of a clean bucket, care being taken 
to draw it forward of the ejection pipe of the condenser. When 
brought on board a thermometer is immersed for a minute and 
the temperature noted. The water is then bottled, tied down, and 
labelled. 
To get water from any desired depth below the surface the 
oldest method is to use a valved-box arrangement. This method 
was devised by Hooke more than two centuries ago, and until 
recently it was the only one employed. When descending, both 
the upper and lower valves (which open upwards) are kept open, 
and the water traverses the arrangement. On pulling up, the 
valves close, and, kept down by the pressure of the water above, 
they preserve the enclosed sample unmixed. A very ingenious 
apparatus of this nature, the cistern thermometer of Sir Eobert 
Christison, was presented to the Station ; but although convenient 
in many ways, it has the defect of uncertainty in action, and the 
result of a long series of trials decided me to employ other methods. 
It was tried to collect deep samples by sinking a stoppered 
bottle to the required depth, and then pulling out the stopper by 
a special line. The two lines were frequently entangled, owing to 
currents making the bottle rotate ; but although this could have 
been remedied, in part at least, by fixing the bottle in a frame 
provided with a vane-shaped attachment, other considerations led 
to the abandonment of the method. When the stopper fitted 
closely, the pressure of the superincumbent water prevented its 
withdrawal by any force less than sufficient to haul the bottle up 
again in spite of a heavy lead attached to it; and when the 
stopper did not fit closely, water from intermediate depths found 
its way in. 
The depths in the Firth of Forth are too small (only in one 
place coming up to 40 fathoms) to permit stopcock water-bottles 
to be used, and the slip water-bottle was consequently adopted for 
general employment. 
The instrument hitherto used was constructed as an experimental 
form for Mr Buchanan, and it is about to be superseded by an 
improved apparatus on the same principle. 
Buchanan’s slip water-bottle consists of a brass body A (fig. 1), in 
