201 



Scientific Observations made during the 

 Voyage of the Maranoa from London to 

 Adelaide, 1883. 



By Clement L. Wkagge, F.E.GLS., F.K.Met.Soc, &c. 



[Read June 2, 1885, and March 2, 1886.] 



Plates XXI.-XXVI. 



(abstract.) 



We left Portland at 6.40 a.m., October 20th, and I at once 

 proceeded to arrange niy instruments. I employed an ordinary 

 Stevenson's thermometer screen, and strongly recommend it for 

 sea use in place of the Board of Trade wall screens, usually sup- 

 plied to captains by the Meteorological Office. By means of 

 it I obtained a better circulation of air around the bulbs than 

 is possible with a wall screen, and I hung maximum and mini- 

 mum thermometers therein, as well as wet and dry bulbs. Self- 

 registering thermometers I find very necessary at sea, and the 

 screen should be swung to a spar in such a way as to keep its 

 perpendicular position, and if placed in the afterpart of the 

 ship, near the taffrail, a good series of observations can be ob- 

 tained, and the index in the minimum thermometer will not 

 slip. Here the chance of vitiation of readings, either by spray 

 or heat from the engine-room, is reduced to its minimum. In 

 my cabin I swung a "Bichard" aneroid barograph, a new form 

 of recording barometer, which I can most cordially recommend. 

 The instrument only needs setting and winding once a week, 

 and a perfect and most valuable record of pressure is obtained 

 throughout the voyage. My own mercurial, a fine Board of 

 Trade barometer, having a total error of but 0003, 1 also hung 

 in ray cabin, and my floating observatory was as complete as I 

 could make it. I also determined to take sea-surface tempera- 

 tures throughout the voyage, as this is one of the most impor- 

 tant points in the problems of physical geography, and I found 

 the best plan was to cast a little bucket from near the fore- 

 castle head, so as to be clear of the disturbing influences from the 

 waste-pipes of the engine-room. At noon on October 20th, 

 28i miles south-west from Portland, I took my first regular 

 readings. Observations were usually made at "eight bells." 



It is always my custom at sea to cast adrift bottles containing 

 the ship's position, with a request to the finder to report where 



