EFFECT OF HARROWING IN AUTUMN. 353 



Temperature at Saint Louis, Mo., of winter of 1876-'77 — Continued. 



1877. 



February 9 

 10 

 11 

 12 

 13 

 14 

 15 

 16 

 17 

 18 

 19 

 20 

 21 

 22 

 23 



Max. 



Min. 



.VIean.l 



1 



50 



33 



1 

 44 



58 



37 



48 



5^ 



42 



52 



52 



29 



32 



36 



23 



33 



44 



30 



38 



53 



31 



44 



47 



38 



40 



50 



34 



42 



66 



34 



53 



58 



34 



37 



48 



27 



39 



65 



34 



51 



! 53 



44 



47 



j 44 



33 



33 



187 



February 24 



25 



26 



27 



28 



March 1 



2 



3 



4 



5 



6 



7 



8 



9 



10 



Max. 



Min. 



35 



23 



33 



28 



43 



28 



48 



28 



50 



32 



47 



39 



47 



37 



49 



18 



32 



14 



40 



26 



55 



30 



57 



36 



5.T 



18 



23 



9 



41 



16 



1. Haerowing in the Autuhn. — To appreciate fully the effect on 

 the eggs of harrowing in the autumn, it is necessary to understand in 

 what manner they are affected by freezing and thawing, as well as by 

 exposure. 



Experiments to test the effects of alternately freezing and thawing. — The 

 eggs in the following series of experiments were obtained early in No- 

 vember, at Manhattan, Kans., under similar conditions. They were 

 mostly in a fluid state at the time, and none but good and perfect masses 

 were used. They were all carefully placed in the normal position at the 

 surface of the ground, in boxes that could be easily removed from place 

 to place. The experiments commenced November 10, 1876, and ended 

 in April, 1877. During November and December the weather was 

 severe, while during January and February it was largely iqild and 

 genial for the season. In March again there was much frost. 



The temperature in the office, into which all the eggs when not exposed 

 were brought, ranged during the day from 65^ to 70° F., rarely reach- 

 ing to 750. During the night it never dropped below 40^, and averag,ed 

 about 550. 



Experiment 1. — Fifty egg-masses were exposed to frost from November 10 to January 

 10, and ilien taken in-doors. In twenty days they commenced hatching, and continued 

 to do so for thirty-eight days thereafter. 



Experiment 2. — Fifty egg-masses exposed at the same time to frost. Brought in-doors 

 on December 10. On December 31 they commenced hatching numerously, and con- 

 tinued to hatch till the 10th of January, 1877, when the remainder were exposed again. 

 The weather being subsequently mild, some hatched on each warm day until the 26 h. 

 None hatched thereafter, and upon examination, subsequently, all were found to have 

 hatched. 



Experiment 3. — Fifty egg-masses exposed at same tim^. Brought in-docrs December 

 1. Kept there till the •22d without any of them hatching. Exposed again for three 

 weeks, and then brought in-doors on the r2th of January. They commenced hatching 

 two days thereafter, and continued till the 29th. Subsequent examination showed 

 them all to have hatched. 



Experiment 4.— One hundred egg-pods exposed at the same time, but alternately 

 brought in-doors and exposed again every fourteen days. Some commenced hatching 

 during the second te.-m in-doors ; others continued during the warm days of the third 

 exposure, and all had hatched by the sixth day of the third term in-doors. 



Experiment 5. — A lot of one hundred egg-masses alternately exposed and brought in- 

 doors every week. During the first four terms of exposure they were continuously 

 frozen, while during the next four the weather was frequently mild enough to permit 

 hatching. They first began to hatch during the fourth term in-doors, and continued to 

 hatch, except during the colder days when exposed, until the seventh term in-doors, 

 during which the last ones escaped. 



23 a 



