A Table of several remarkable Periodical Birds, exhibiting the mean temperature of those days on which they have appeared and dis 
Neighbourhood of Manchester during the last five years, as deduced from observations on a pair of Rutherford’s horizontal self-registerin 
exposed to the open air in a shady situation; the general means, or the means of the total number of observations accompanying each gpeci i 
‘lifference of the means both general and particular, being also given. When the mean temperature at the time of the disappearanes ee with the 
exceeds the mean temperature at the lime of its appearance, the sign + is prefixed to the difference, the sign — being prefixed wRedera cn 
n- 
trary occurs. 
appeared in the 
g thermometers, 
Mean Mean 1819. Mean | 1820 Mean Mean 
BIRDS. EL Temperature. isis Temperature. Temperature. | Temperature. WING Temperature Mens. 
= —EEEE S| —— 2 ans. 
; ; appeared. ... April 3 ol Ks March 27 40° March 31 54° April 4 55 ° April 9 53.°5 as 
Sand Martin Tae pearal Sept. 17 64.5 Sept. 15 58.5 Sept. 21 49 | Sept. 14 66.5 | Sept. 14 re ri ie 
Difference of means... + 13.5 + 18.5 — 1) 4+ 11.5 oa Daa wens | 
~Cappeared....| April 19| 43 | April 8 | 48e April 7 | 56 | April7 | 46.5 |April17| 44.5 i 
Willow Wren ie bare Sept. 12 62.5 Sept. 13 55 Sept. 7 61 | Sept. 3 62 Sept. 7 64.9 cae 
= Seer — = = = : 
Difference of means... + 19.5 ap are 2) | |+ 15.5 19.7 |413.3 | 
appeared....| April25| 42 = |April 15) 52.5 = | April 11) 52 | April27| 44 April20| 49 ; 
Swallow sss. { didappeared| Oct.9 | 51.5 | Oct.20| | 66 Oct.15 | 49 Sept.90| 48.5 | cull | 627 | ane 
Difference of means... + 9.95 + 3.5 — 8 + 4.5 PR: 7 lth sya 
aa | ——— | }--—-. — =| 
; appeared. ...| May 6 a3 April 19 42.5 April 15 | 48 April 26 49.5 April 22 51 48. 
Martin .ses+eeee A eearall Oct. 12 45.5 Oct. 20 56 Oct. 20 52 Oct. 8 50 Sept. 30 51 50 9 
=a = | ta eae 
Difference of means... —- 7.5 + 13.5 rie) 9A \+ 5 0 dL Ohi 
appeared. ...] May 9 47.5 April 25 40 April 15 48 April 19 54.5 a April 22 dl 48.2 i 
Cuckodsessesere eral June 25 72 June 17 64.5 June 23 61.5 Fie 30 61 wane 28 56 63 
Difference of means... + 24.5 ; 
Swilteccooeccee. § 2PPEae’: +--| May 10 50. 5 May 1| 41.4 May 5 52 May 2 53.5 | May 19 48 49.1 
disappeared. Aug. 11| 6 Aug.15| 60 Aug. 12) 69 Aug. 12 63.5 |Aug.14,.| 89.2 61.5 
Difference of means... + 5.5 + 18.5 + 17 + 10 x + 11.2 412.4 
ee saline April2| 52.5 March 13] 40 March 24| 43 April3 | 54 March 5| 37.5 | 45.4 
“9 appeared....! Oct. 10] 49 Oct. 15 57.5 Sept. 29) 53 Sept.26| 47 Oct.19 49, 2 51.1 
Difference of means... + 3.5 — 17.5 = 10) Hee ei SS Vo Ged 
7 disappeared. March 25) 45 March 26 40 Tah en ran: 
OETA cones PP rc arch 0 March 18} 40.5 |March 20} 43 Feb. 25] 34 40.5 
appeared. ...| Oct.29] 41.5 | Nov. 2| 453 Nov.4| 51.5 |Nov.11] 41.5 | Oct.25} 47.5 47.4 
+ 3.5 
Difference of means... 
— 16 = ll Joi 
