210 Instructions for Making and Registering tyc. [Jaw, 



attached Thermometer, with that of the external Thermometer, and 

 a column of Remarks for Wind and Weather, as being the most 

 essential and indispensable elements of Meteorology; but it is in the 

 power of any one who pleases to supply additional information, and 

 to those who have leisure, instruments, and inclination for the task, 

 the Committee would particularly recommend the regular observation 

 of the Wet Thermometer, those of the Self-registering Thermometer 

 and Weekly or Monthly Observations of Thermometers buried at 

 different and progressiv e depths beneath the surface of the soil. 



The printed forms provide for the arithmetical convenience of cast- 

 ing up the means for each month. In doing so, it is requested that 

 care will be taken to verify the results by repetition, and (that usual 

 sources of error may not escape notice) they recommend in every 

 instance, before adding up the columns, to look down each to see that 

 no obvious error of entry (as of an inch in the barometer, a very com- 

 mon error, or what is more difficult of detection, an error in the first 

 decimal place) shall remain to vitiate the mean result. It is perhaps 

 unnecessary to do more than mention the precaution of counting the 

 days in each column on which observations occur, so as to admit of no 

 mistake in the divisor, and to use throughout the decimal arithmetic in 

 calculating the mean results. Care and exactness in these points will in 

 most cases add greatly to the value of the communications, as it well 

 be quite impracticable for the Committee, should observations flow in 

 in masses, unreduced or erroneously reduced, to undertake the over- 

 whelming task of recomputing them. 



Although not, strictly speaking, a branch of meteorology, yet as the 

 collection of observations of the Tides has been made a part of the 

 duties of your Committee, they propose the following stations as points 

 where it would be especially desirable to obtain regular observations of 

 the time and height of high and low water, according to the rules and 

 on the plan proposed by Mr. Whewell, in his late researches on this 

 subject, and they earnestly invite communications on this head from any 

 residents at those ports who may have leisure and take interest enough 

 in the important questions connected with the subject. 



In Cape Town and Simon's Bay, they have the pleasure to report, 

 that a series of observations under the superintendence of Captain Bance 

 and Mr. Levien have already been undertaken at the instance of the 

 Astronomer-Royal, and are now inactive progress. 



Cape Town, 

 Simon's Bay, 

 Port Elizabeth, 

 Knysna, 

 Saldanha Bay, 



Ascension, 

 Mauritius, 

 Tristan d'Acunha, 

 Madagascar, 

 Mozambique. 



