Of the Spring Months of the Year 1855. 29 



up the soil ; and farming operations were in consequence much delayed. 

 With the arrival, however, of the genial weather, vegetation advanced 

 with amazing rapidity ; and the hay and other crops were very little, if 

 at all, later than usual. Neither was the long drought followed by any 

 unusual fall of rain. 



The penetration of the frost would depend much on the nature of the 

 soil. The following estimate has been formed by a skilful farmer and 

 highly intelligent man in the Lewis, a friend of the Kev. James Gunn, 

 whose kindness we have already acknowledged, and by whom this infor- 

 mation also is sent to us : — 



1. Into moss on -which heath grows, the frost penetrated . 6 inches. 



2. Moss on which no heath grows, . . . . .9 — 



3. Arable land in field or garden, 12 — 



In comparison to these, the frost of 1856 did not jiienetrate above 

 one-fourth the depth. Mr. Miller of Eastwood makes the same esti- 

 mate for arable land about Glasgow, viz., 12 inches. 



As bearing on this point, Professor C. Piazzi Smyth has been so good 

 as to furnish us with a copy of the register of the deep soil thermo- 

 meters kept by him, and examined and entered weekly. We subjoin (see 

 Table) the record of only two of these, t^ and ^5, respectively at three feet 

 and one-tenth of a foot in the soil — the others at six, twelve, and twenty- 

 four feet being too deep for our purpose. Of the latter, Professor Smyth 

 says, in a letter to us on September 8, 1855 — " They are still suffering 

 under last winter's cold, so slowly does the wave of annual temperature 

 travel downward through the soil." 



The indications given in the appended Table, drawn up from data 

 kindly furnished by Professor C. P. Smyth, correspond with those of 

 the other Tables. The thermometer t^, one-tenth of an inch under the 

 surface, read lowest on the 19th February ; t^ at three feet, on the 26th, 

 or ten days after ; and the readings generally are the lowest at or soon 

 after the time of greatest cold, — a considerable rise taking place between 

 the 2d and 9th of April — the 6th of that month, as already remarked, 

 having been the day on which the frost finally broke up. The monthly 

 means are given for four months of 1855 and the four previous years, in 

 order to place the contrasts of temperature in a more striking light. 

 The means for 1851-4 are taken from the Tables given in the last 

 published or eleventh volume of the Edinburgh Astroiwmical Observa- 

 tions. These Tables embrace the entire series of observations of the 

 Earth-thermometers since 1838, carefully reduced, and accompanied by 

 descriptive and explanatory matter from the pen of Professor Forbes, 

 and a brief statement of some of the results by Her Majesty's Astrono- 

 mer for Scotland. A full exposition of the significancy of these Tables, 



