336 Instructions for \Icttoroloyical Observaiions. 



they require is sim))le, ami by no means cosily, and may be 

 constructed indeed by any one for himself will) case. 



If the Commitlce in ibis their first Report do not dilate on 

 this and other of the le^s usually practised observations of 

 JVIetcorology, it is becaxise they wish for the present chiefly to 

 call attention to the accumulation of reffular and daily observa- 

 tions of a more definite and numerical character With thiJ 

 view they have drawn up, and by the liberal aid of Government, 

 have procured to be printed skeleton forms, of which a copy is 

 annexed, for immediate distribution among such Correspondents 

 of the Institution, and others, as may be willing to undertake 

 their filling up. These comprise, it is true, only the registers 

 of the Barometer and its attached Thermometer, with that of 

 the external Thermometer, and a column of Remark 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 so supply additional information, and to thOjC who 

 have leisure, instruments, ai.d inclination for the task, the Com- 

 mittee would particularly recommend the regular observation 

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

 momatcr, and Weekly or Monthly Observations of Thcrmorac- 

 ters buried at different and progressive depths beneath tlie 

 surface of the soil. 



The printed forms provide for the arithmetical convenience 

 of casting up the means for each month. In doing so it is 

 requested that care will be taken to verify the results by repeti- 

 tion, 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 common 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 

 more than mention the precaution oi counting the days in e<i(h 

 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 com- 

 municatioiis, as it will be quite impracticable for the Committee, 

 should observations flow in masses, unreduced or erroneously 

 reduced, to undertake the overwhelming 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 whcra 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 



