Climate and Health in Hot Countries and the Outlines of Tropical Climatology / A Popular Treatise on Personal Hygiene in the Hotter Parts of the World, and on the Climates That Will Be Met Within Them.

by George Michael James Giles

Notes on the Observation of Meteorological Data.

Few houses will now be found without a thermometer and barometer, and many people are fond of keeping a register of their observations. Moreover, where the observer chances to be stationed in an out-of-the-way place, even a casual domestic register of this sort may be of considerable value. . . . The instruments required are the wet and dry bulb thermometers, a rain gauge, and a barometer.

Those who have to move about in the backwaters of civilisation, will probably find the mercurial barometer rather a “white elephant,” as it requires great care and attention whenever it is necessary to move it; and for such, a good aneroid is a more desirable possession. It is, of course, important that the instrument should be compared, whenever opportunity occurs, with a standard mercurial instrument; but for merely observing extent of fluctuation an aneroid is quite accurate enough for all practical purposes. The rain gauge must of course be set up in some open and unsheltered position near the ground level, and the thermometers should be hung in a north verandah (for the northern hemisphere) against a piece of felt which will help to protect them from the heat radiated from the wall. The aneroid, on the other hand, may be hung in any position where it is well protected from the weather—on the ground-floor. The direction of the wind can easily be observed by means of a small triangular flag or burgee hoisted to a pole, which, unless the neighbourhood be a very open one, is best lashed up in a tree so as to project above its branches.

Those, however, who desire to take up the study of their local meteorology seriously, will do well to obtain a little pamphlet, entitled “Hints to Meteorological Observers,” by W. Marriott, published at 1s. 6d., under the auspices of the Royal Meteorological Society, by E. Stanford, 12, Long Acre, W.C., which contains complete instructions on the subject.

From the point of view of the tropical resident, it is unfortunate that some of the tables in this publication are hardly carried high enough, but the instructions will enable anyone to amplify them. On this account, I append a table for calculating relative humidity of a less elaborate sort, but more extended than that furnished in the pamphlet, as this is one of the most important of all climatic factors from a sanitary point of view.

The table is only worked out to half degrees of difference between the wet and dry bulb instruments, and for the most part to 4° intervals of the dry thermometer, but it is easy, by reading between the lines, to fill up the gaps, where any marked interval exists; and it will be observed that at the lower right-hand corner of the second table, the numbers progress in regular arithmetical progression, so that it is not difficult to infer the percentages in cases of somewhat higher degrees of temperature and dryness.

Table for Calculating the Relative Humidity of the Atmosphere %by the Dry and Wet Bulb Thermometer.
Difference of Wet and Dry Bulbs	Reading of the Dry Bulb Thermometer.																				Difference of Wet and Dry Bulbs
	32°	34°	36°	38°	40°	44°	48°	52°	56°	60°	64°	68°	72°	76°	80°	84°	88°	92°	96°	100°
0·5	92	94	95	95	96	96	96	96	97	97	97	97	97	97	98	98	98	98	98	98	0·5
1	87	89	91	91	92	92	92	93	93	93	94	94	94	95	95	95	95	95	95	95	1
1·5	81	84	86	87	88	88	88	89	89	90	91	91	92	93	93	93	93	93	93	93	1·5
2	76	80	82	83	84	84	85	86	87	88	88	89	89	89	90	90	91	91	91	91	2
2·5	70	75	78	79	80	81	82	83	83	84	85	85	86	87	87	87	88	88	88	89	2·5
3	65	71	74	76	76	78	79	80	81	82	82	83	83	84	85	85	85	85	86	87	3
3·5	60	66	70	72	73	75	76	77	78	79	80	81	82	82	83	83	83	83	84	85	3·5
4	56	62	66	69	70	72	73	74	75	76	77	78	79	80	80	81	81	81	82	83	4
4·5	52	58	62	65	66	69	70	71	72	74	75	75	76	79	78	78	79	79	80	81	4·5
5	48	55	59	62	63	65	67	69	70	71	72	73	74	75	76	76	77	77	78	79	5
5·5	45	52	56	59	61	62	64	65	67	69	70	71	72	73	74	74	75	75	76	77	5·5
6	41	49	53	56	58	60	62	63	65	66	68	69	70	71	72	72	73	73	74	75	6
6·5	38	46	50	53	55	57	59	61	62	64	65	67	68	68	69	70	70	71	72	73	6·5
7	35	43	47	50	52	55	57	59	60	62	63	65	65	66	67	68	68	69	69	70	7
7·5	32	40	44	48	49	52	54	56	58	60	61	62	63	64	65	66	66	67	68	69	7·5
8	30	37	42	45	47	50	52	54	56	58	59	60	61	63	64	64	65	66	67	68	8
8·5	29	35	40	42	44	48	50	52	54	56	57	58	60	61	62	63	63	64	65	66	8·5
9	27	33	38	41	42	46	48	50	52	54	55	56	58	59	60	61	61	62	63	64	9
9·5	25	31	36	38	40	43	46	48	50	52	53	54	55	57	58	59	60	61	62	63	9·5
10	23	30	34	36	38	41	44	46	48	50	52	53	54	56	57	57	58	59	60	61	10
10·5	21	28	32	34	36	40	42	44	46	48	50	51	52	54	55	56	57	58	59	60	10·5
11	19	26	30	32	34	38	40	43	45	46	48	50	51	52	53	54	55	56	57	58	11
11·5	17	24	28	30	32	36	38	41	43	45	46	48	49	50	52	53	54	55	56	57	11·5
12	16	23	27	29	31	34	36	39	41	43	45	46	48	49	50	51	52	53	54	55	12
12·5	15	21	28	27	29	32	34	37	39	42	43	45	46	47	48	49	51	50	53	54	12·5
13	14	20	24	26	28	31	33	36	38	40	42	43	45	46	47	48	50	51	52	53	13
13·5	13	18	23	25	27	30	32	35	36	38	40	41	43	45	46	47	48	49	50	51	13·5
14	12	17	22	24	25	28	30	33	35	37	39	40	42	43	45	46	47	48	49	50	14
14·5	11	16	21	22	24	26	29	31	34	36	37	39	40	42	43	45	46	47	48	49	14·5
15	10	15	20	21	23	25	28	30	33	35	36	38	39	41	42	43	44	45	46	47	15
15·5	10	14	18	20	22	24	26	28	31	33	35	37	38	39	41	42	43	44	45	46	15·5
16	9	13	17	19	21	23	25	27	30	32	34	35	37	38	39	40	42	43	44	45	16
16·5	8	12	16	18	20	22	23	26	29	31	33	34	36	37	38	39	41	42	43	44	16·5
17	7	12	15	17	19	21	22	25	27	30	31	33	34	36	37	38	39	41	42	43	17
17·5	7	11	14	16	18	20	21	24	26	28	30	32	33	35	36	37	38	39	40	41	17·5
18	6	10	13	15	17	19	20	23	25	27	29	31	32	34	35	36	37	38	39	40	18
18·5	—	—	—	—	—	—	19	22	24	26	28	30	31	33	34	35	36	37	38	39	18·5
19	—	—	—	—	—	—	18	20	23	25	27	29	30	32	33	34	35	36	37	38	19
19·5	—	—	—	—	—	—	17	19	21	24	26	28	29	31	32	33	34	35	36	37	19·5
20	—	—	—	—	—	—	17	18	20	23	25	27	28	30	31	32	33	34	35	35	20

Table for Calculating the Relative Humidity of the Atmosphere % by the Dry and Wet Bulb Thermometer.
Difference of Wet and Dry Bulbs	Reading of the Dry Bulb Thermometer.										Difference of Wet and Dry Bulbs
	32°	34°	36°	38°	40°	44°	48°	52°	56°	60°
0·5	92	94	95	95	96	96	96	96	97	97	0·5
1	87	89	91	91	92	92	92	93	93	93	1
1·5	81	84	86	87	88	88	88	89	89	90	1·5
2	76	80	82	83	84	84	85	86	87	88	2
2·5	70	75	78	79	80	81	82	83	83	84	2·5
3	65	71	74	76	76	78	79	80	81	82	3
3·5	60	66	70	72	73	75	76	77	78	79	3·5
4	56	62	66	69	70	72	73	74	75	76	4
4·5	52	58	62	65	66	69	70	71	72	74	4·5
5	48	55	59	62	63	65	67	69	70	71	5
5·5	45	52	56	59	61	62	64	65	67	69	5·5
6	41	49	53	56	58	60	62	63	65	66	6
6·5	38	46	50	53	55	57	59	61	62	64	6·5
7	35	43	47	50	52	55	57	59	60	62	7
7·5	32	40	44	48	49	52	54	56	58	60	7·5
8	30	37	42	45	47	50	52	54	56	58	8
8·5	29	35	40	42	44	48	50	52	54	56	8·5
9	27	33	38	41	42	46	48	50	52	54	9
9·5	25	31	36	38	40	43	46	48	50	52	9·5
10	23	30	34	36	38	41	44	46	48	50	10
10·5	21	28	32	34	36	40	42	44	46	48	10·5
11	19	26	30	32	34	38	40	43	45	46	11
11·5	17	24	28	30	32	36	38	41	43	45	11·5
12	16	23	27	29	31	34	36	39	41	43	12
12·5	15	21	28	27	29	32	34	37	39	42	12·5
13	14	20	24	26	28	31	33	36	38	40	13
13·5	13	18	23	25	27	30	32	35	36	38	13·5
14	12	17	22	24	25	28	30	33	35	37	14
14·5	11	16	21	22	24	26	29	31	34	36	14·5
15	10	15	20	21	23	25	28	30	33	35	15
15·5	10	14	18	20	22	24	26	28	31	33	15·5
16	9	13	17	19	21	23	25	27	30	32	16
16·5	8	12	16	18	20	22	23	26	29	31	16·5
17	7	12	15	17	19	21	22	25	27	30	17
17·5	7	11	14	16	18	20	21	24	26	28	17·5
18	6	10	13	15	17	19	20	23	25	27	18
18·5	—	—	—	—	—	—	19	22	24	26	18·5
19	—	—	—	—	—	—	18	20	23	25	19
19·5	—	—	—	—	—	—	17	19	21	24	19·5
20	—	—	—	—	—	—	17	18	20	23	20

Difference of Wet and Dry Bulbs	Reading of the Dry Bulb Thermometer.										Difference of Wet and Dry Bulbs
	64°	68°	72°	76°	80°	84°	88°	92°	96°	100°
0·5	97	97	97	97	98	98	98	98	98	98	0·5
1	94	94	94	95	95	95	95	95	95	95	1
1·5	91	91	92	93	93	93	93	93	93	93	1·5
2	88	89	89	89	90	90	91	91	91	91	2
2·5	85	85	86	87	87	87	88	88	88	89	2·5
3	82	83	83	84	85	85	85	85	86	87	3
3·5	80	81	82	82	83	83	83	83	84	85	3·5
4	77	78	79	80	80	81	81	81	82	83	4
4·5	75	75	76	79	78	78	79	79	80	81	4·5
5	72	73	74	75	76	76	77	77	78	79	5
5·5	70	71	72	73	74	74	75	75	76	77	5·5
6	68	69	70	71	72	72	73	73	74	75	6
6·5	65	67	68	68	69	70	70	71	72	73	6·5
7	63	65	65	66	67	68	68	69	69	70	7
7·5	61	62	63	64	65	66	66	67	68	69	7·5
8	59	60	61	63	64	64	65	66	67	68	8
8·5	57	58	60	61	62	63	63	64	65	66	8·5
9	55	56	58	59	60	61	61	62	63	64	9
9·5	53	54	55	57	58	59	60	61	62	63	9·5
10	52	53	54	56	57	57	58	59	60	61	10
10·5	50	51	52	54	55	56	57	58	59	60	10·5
11	48	50	51	52	53	54	55	56	57	58	11
11·5	46	48	49	50	52	53	54	55	56	57	11·5
12	45	46	48	49	50	51	52	53	54	55	12
12·5	43	45	46	47	48	49	51	50	53	54	12·5
13	42	43	45	46	47	48	50	51	52	53	13
13·5	40	41	43	45	46	47	48	49	50	51	13·5
14	39	40	42	43	45	46	47	48	49	50	14
14·5	37	39	40	42	43	45	46	47	48	49	14·5
15	36	38	39	41	42	43	44	45	46	47	15
15·5	35	37	38	39	41	42	43	44	45	46	15·5
16	34	35	37	38	39	40	42	43	44	45	16
16·5	33	34	36	37	38	39	41	42	43	44	16·5
17	31	33	34	36	37	38	39	41	42	43	17
17·5	30	32	33	35	36	37	38	39	40	41	17·5
18	29	31	32	34	35	36	37	38	39	40	18
18·5	28	30	31	33	34	35	36	37	38	39	18·5
19	27	29	30	32	33	34	35	36	37	38	19
19·5	26	28	29	31	32	33	34	35	36	37	19·5
20	25	27	28	30	31	32	33	34	35	35	20

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