310 



AMERICAN BEE JOURNAL 



September 



which were made in Dr. Phillips' lab- 

 oratory. 



As Berlepsch already stated, it is 

 now generally known that the tem- 

 perature in the brood nest in spring 

 and summer is about 37 deg. C (98 

 deg. F.I This warmth must be pro- 

 duced either by the surrounding bees 

 or by the brood itself. The latter is 

 little probable, because it is clear 

 that eggs and little worms cannot 

 produce warmth enough. It is even 

 a question whether the older brood 

 is but a consumer of warmth (pro- 

 duced by adult bees) or whether it 

 may generate some warmth itself. 

 To solve those and other questions, 

 I made the following experiments: 



1 wished to measure the inner tem- 

 perature of bees and brood with an 

 electric thermometer. The principle 

 of this is a simple one. If we form a 

 circle by two different metal threads, 

 for instance of platinum and copper, 

 there will be produced an electric 

 current if the temperature of one 

 soldering is higher than the tempera- 

 ture of the other. An exact and most 

 sensitive galvanometer shows us the 

 relative importance of the current. 

 With the help of a professor of phys- 

 ics, 1 constructed a fine needle, which 

 was formed by soldering a thread of 

 platinum, 3-32 m m of diameter, with 

 a thread of copper. 5-32 m m. The 

 other soldering of the platinum 

 thread with a thicker copper thread 

 was about 1 cm from the point. The 

 whole needle was fixed in a cramp 

 and near the soldering of the plati- 

 num with the thick copper thread 

 we placed an exact thermometer. 

 The only fear I had was that it 

 would perhaps be difficult to deter- 

 mine the exact temperature of the 

 bee, because I supposed that at once 

 a great loss of warmth would arise 



in three different manners: 



1. The bee immediately ceases to 

 produce warmth and therefore be- 

 gins to cool by irradiating its 

 warmth: however, this loss is sig- 

 nificant and slow. 



2. The threads of platinum and 

 copper draw off by conduction a cer- 

 tain portion of the warmth of the 

 surrounding animal matter. 



3. The greatest loss arises, per- 

 haps, by the formation of the elec- 

 tric current, because the current is 

 formed by absorbing the surround- 

 ing warmth. 



The success showed that my fear 

 i 11 founded. To prove it I made 

 a number <>t" experiments where we 

 noted tile temperature shown by the 

 galvanometer, lirst every 10 scc- 

 onds, and later every 5 seconds. 1 

 will give tlie result of a single ex- 

 periment, No. 47: A Hying bee which 

 was pierced with the thermo needle 

 into (lie breast. The temperatures 

 shown mi tin galvanometer were: 



After 5 seconds 29.4 deg. C 



Vftei l 11 nds 34.5 deg. ( 



Aft. , 15 seconds 36.2 deg. C 



JO seconds 36.1 deg. (. 



After 25 seconds 34.8 deg. I 



30 seconds 33.3 



Aftei I 31 " 



After 40 seconds 30.2 deg. C 



After 45 seconds 28.9 deg. C 



After 50 seconds 27.5 deg. C 



After 55 seconds 26.4 deg. C 



After 60 seconds 25.3 deg. C 



After 65 seconds 24.4 deg. C 



After 70 seconds 23.4 deg. C 



After 7? seconds 22.7 deg. C 



After 80 seconds 22.0 deg. C 



The other experiments showed the 

 same scale and we established that 

 the maximum was reached always af- 

 ter 15 seconds. 



Of course, this maximum does not 

 correspond to the beginning tem- 

 perature, because in those IS seconds 

 the temperature of the surrounding 

 medium will sink steadily. It would 

 be the same if you wished to weigh 

 a little portion of ether in an auto- 

 matic balance; you would not be able 

 to get the true weight, because a 

 great deal of the ether would be 

 evaporated , if the hand had reached 

 its maximum. With the help of 

 mathematical speculations, I could 

 find that the real temperature — be- 

 tween the limits in question — would 

 be about 1J4 to 2 degrees C. higher 

 than the first maximum shown by the 

 galvanometer. 



I was certain to get the best re- 

 sults by piercing the bee in the 

 breast, because there the inner body 

 is most compact, while in the head, 

 as well as in the abdomen, there are 

 many air sacs. When I did not suc- 

 ceed in piercing the breast of the bee 

 in a correct way, I got less tempera- 

 tures; for instance, when the point 

 of the needle penetrated the thorax 

 so that it became visible, the tem- 

 peratures of the abdomen were all 

 10 to 15 degrees lower than those of 

 the breast; therefore, I did not note 

 those results, with the exception of 

 2 or 3. The temperatures of the bee 

 breast alone are to be considered as 

 standard. 



As to the temperature of the brood, 

 I could only make experiments with 

 capped brood, because, for my 

 needle of 5 mm length, the worms 

 were too little. It is natural that 

 also with the brood I did not always 

 succeed in pricking exactly enough, 

 therefore some of my results may be 

 too low. 



The first five series are made with 

 a mating box with three movable 

 frames 12x6 in. with a fertile queen 

 and with brood up to about 17 days. 

 The other experiments were made 

 with a queenless section of my con- 

 struction, i. c. a single frame of 15x 

 4 l / 2 in., with brood also about up to 17 

 days, and later on with a few queen- 

 cells. 

 1. April 15.— Outer temperature 15 



deg. C (59 deg. F.) All bees living 

 ones. 



1, 5'i' 



2.— 32.1 deg. 



3. — 34.5 deg. 



4.-37.5 cleg. (99 cleg. F.) 



5.— 35.0 deg. 



6.-33.7 deg. 



2. April 18— Outer temperature 15' . 



deg. (' (5(1 deg. F.) 



(a) Fanning lues before the 

 flight hole. 

 7.— 31.7 deg. 

 8.— 36.0 deg. 

 9.-38.7 deg. (102 deg. F.) 



10.— 35.2 deg. 



(b) Returning bees. 

 11.— 31.8 deg. 



12.— 33.5 deg. 



13.— 36.5 deg. 



14.— 31.0 deg. 



15.— 38.8 deg. 



16.— 33.0 deg. 



No. 14 had been caged in a metal 

 liox for 10 minutes. No 16 had been 

 sitting for some minutes idly on a 

 window. 



(c) Flying off bees. 

 17.— 34.1 deg. 



18.— 39.0 deg. (102 deg. F.) 



19.— 37.7 deg. 



20.— 38.0 deg. 



21.— 29.2 deg. (abdomen) 



22.-39.2 deg. 



3. April 20 — Outer temperature 7 

 deg. C. (44^ deg. F.) All bees had 

 been caught on the flight hole with a 

 pincer. 



23. — 23.1 deg. (abdomen. Immediate- 

 ly after this, breast 28.6 deg. 



24.— 32.0 deg. 



25.-36.3 deg. 



26.— 36.0 deg. 



27.-37.2 deg. 



28.-32.8 deg. 



29.-36.3 deg. 



30.— 34.5 deg. 



31.— 36.0 deg. 



32.-36.6 deg. 



33.-36.7 deg. 



34.-37.4 deg. 



35.— 38.1 deg. 



36.— 33.0 deg. 



37.-37.7 deg. 



38.-37.7 deg. 



39.-32.4 deg. 



40.— 33.5 deg. 



41.— 38.2 deg. 



42.-37.3 deg. 



43.-38.9 deg. 



44.-37.3 deg. 



No. 45 had been spit, but flew off 

 after being caught ; spit once more. 



4. April 25— Outer temperature 15 

 deg. C. (59 deg. F.) 



46.— 34.9 deg. 



47.— 38.1 deg 



48.— Drone going to fly_— 36.0 deg. 

 49. — Young bee on window 33.1 deg 

 50. — Young bee on window s35.8 deg 

 51. — Young bee on window 34.9 deg 

 52.— Old bee on window.— 36.5 deg 

 53. — Old bee on window.— 36.0 deg 

 54.— Old bee < n window— 39.1 deg 

 (102 F.) 

 S5._01d bee on window— 38.0 deg 

 56. — Old bee on window — 37.5 deg 

 S7._OUl bee on window— 37.6 deg 

 Brood, white nymphs. 

 58. — 45.2 deg. (113 deg. F.) 

 59.— 37.8 deg. 

 60.— 38.7 deg. 

 61.— 36.0 deg. 

 02.— 35.5 deg. 

 63.-34.3 deg. 



It is easy to recognize that the 

 biood was cooling, the box being 

 opened and the bees not very numer- 

 ous. 



5. April 26— Outer temperature 15 

 deg. C. (59 deg. F.) 



64.— Drone on comb 40.7 deg. 



(105 deg. F.) 



65. — Drone on comb 37.5 deg. 



66. — Drone on comb 38.5 deg. 



67,— Brood, about 14 days old 



43.0 deg.(109deg.F.) 



