242 Apparatus for preventing Pipes Bursting during Frost. liquid on a return of temperature. But in that case it is not so certain that the piston would descend to its original position and open the cock. Indeed, unless the combined friction of the piston and cock was very small it would not. Besides, it being a primary object of the plan to empty the pipes at the moment of shutting off the water, it would be necessary in that case to employ two cocks-one for each purpose. To obviate this I have, therefore, thought it preferable to employ a double-action valve of the description indicated in the diagram, both as regards the relative simplicity of action in a valve to that of a stop-cock, and, what is of greater importance, with the view of effecting, at the same time, the shutting off of the water and the emptying of the pipes. Explanation of the Plate (III.)-Fig. 1 is a section; fig. 2, an elevation of the apparatus about one-fourth of full size. A represents the junction of the ingress supply-pipe, which performs a curve into the top of the double-action valve B. C is the supply-pipe continued on its ascent to the cistern. D is the waste-pipe through which the pipes are emptied. E is the small copper tube containing a measured quantity of water; it is supported by a small bracket attached to the pipes. F is the piston accurately fitting into the copper tube, and acting in direct conjunction with the valve in B. O is an airvessel. Now, if frost act on the small copper tube, the water it contains is the first to freeze, expand, and elevate the piston, which in its turn pushes up the valve from its present seat, and shuts it with great force against the projected extremity of the ingress supply-pipe. A passage is thus opened between the ascending supplypipe C and the waste-pipe D, through which the whole water in the pipes immediately escapes. By this means the water is shut off, and the pipes emptied at the same time. By observing that the valve shuts against the pressure of the water, it is evident that so soon as the water again becomes fluid, it must exert that whole pressure on the valve before it can escape, and it thus constitutes the external pressure, if any were required, to depress the piston when the temperature returns to its normal state. This construction of valve overcomes the only remaining difficulty to the effective working of the apparatus. It should be attached to the supply-pipe at the very lowest part of it. The place where the pipe enters the house-often that of the cellar, area, or other low, exposed situation-is the best. The water-pipes should possess a downward inclination to this point-as, indeed, is generally the case -for the purpose of being completely emptied. Mr Charles Baldwin, civil engineer, of Boston, United States, to whom I am indebted for much valuable information on this subject, suggests that an instrument of this kind might with advantage be employed to indicate the sudden approach of frost. Other applications of a similar nature may very likely be made. Meantime, I rest content with pointing out the existence of a principle which is WEIGHT OF AIR. TEMPERATURE OF AIR. Rain in Inches. Days of Rain fall. Prevailing Winds. January,. 29-402 29-317 235 July,. 29.650 29-419 381 4.32 4:40 2.88 41.5 39.9 45.8 35.9 40.4 40.9 38.2 3.05 13 SW.; W. 19 W.; sw. 1.70 14 EY.; WY. October,... 29-584 29.4 ⚫304 3.48 Means at 29-742 29-581 284 29.892 3.26 47.8 44.7 53.9 42.5 47.1 47-441-131-24 180 W.; SW.; SE. racteristics of another. counteract the destructive consequences which are the ordinary chacation of the expansive force of one body of water, while freezing, to ledged, and which may be described, in a word, as the simple applicalculated to supply a desideratum long and universally acknow THOMSON, F.R.S.E., Lecturer on Chemistry in the University Climate and Mortality of Glasgow, 1851. By ROBERT DUNDAS of Glasgow. The mean height of the barometer, corrected, for the year, was 29.742 inches, and reduced to the level of the sea, 29-892 inches; this very nearly approaches the usually-assumed barometric pressure at the sea-level, or 29.92 inches, the difference being only in deficiency as respects the year. The pressure of dry air at the level of the sea, would be 29.581 inches. The pressure of vapour in the air during eleven months, was 284 inch, and the vapour in a cubic foot of air 3.26 grains. The total fall of rain was 31.24 inches; the mean of five preceding years being 34.04, and of six years, including the present, 33-6 inches. The number of days on which rain fell was 180, giving an average of nearly 3 days per week; the greatest number of rainy days being in January, and the least in September. The greatest height of the barometer during the year was 30-503 inches, on the 28th December, or at the level of the sea it would have stood at 30.653 inches. It was remarkable that at this period, when the barometer was considerably above 30 inches, the atmosphere was generally obscured by thick fogs and by frequent drizzle, with the wind from the S. and SE. The lowest depression of the barometer was 28-736, on the 14th July, with a S. wind, accompanied with a fall of rain (61) upwards of half-an-inch in depth in twenty-four hours. The range of the barometer has therefore been 1.897 inches. The distribution of the temperature of the year has been somewhat irregular. The month of January was remarkably mild, the mean heat being 41°.5 or about 7° above that of the year 1850 (34°3); and notwithstanding the wetness of the season, the first two months of the year were not unfavourable to health. The mean temperature of the first half of the year was 45° 3, of the second half, 49°5, and the mean of the whole year, 47°4 -a number considerably higher than could be anticipated from the latitude. It remains to be ascertained, by future observations, whether the excess of temperature over calculation is dependent on local causes. The mean temperature to the west of the city, during the year 1850, was found by Mr James King, at 9 A.M., 47°-6, and at 9 P.M., 47°-7; and by applying the Greenwich corrections, these numbers become a mean of 48°, affording a close approximation to the results of the present The instruments were compared with the Greenwich standard. The highest temperature attained during the summer was 82°-4, on the 30th June, and during the two preceding days the maximum thermometer reached 80°6 and 81°1,—a rare circumstance in this latitude. The highest heat at Greenwich Observatory, at the same period, was 87°, with a westerly wind. The lowest temperature of the year was 25°9, on the 3d December, making a difference in the extremes for the year of 56° 5. The connection of the temperature with the mortality, in the different months, will be best observed by constructing a table on the following plan:-- year. Mortality and Temperature in Different Months in 1851. March. April. Mean Temperature, 415 409 41-3 44-3 60-1 511 56-5 56-8 529 501 38-4 427 Above 60 years,...... ... Zymotic,.. Consumption,...... Diseases of Lungs,... Mortality at all ages, 774 814 1046 886 877 772 784 943 845 887 903 1124 104 109 77 89 97 97 88 118 298 312 275 300 413 350 384 379 161 156 154 154 166 146 131 153 64 72 54 53 50 50 59 93 180 442 207 153 The effect of cold on the total mortality is sufficiently obvious in November and December, and particularly on the aged and consumptive subjects. There can be less hesitation in tracing the increased deaths, in some measure, to the depression of temperature, as no epidemic prevailed peculiarly in these months. The fall of the temperature from 45° to 28°, destroys, in London, from 300 to 500 lives. Hence we can readily understand how it may have happened, that a considerable portion of the 237 cases of excess of mortality in December over October, may have been due to the operation of this depressing influence during the cold month of November. The effect of temperature may probably appear more striking from a comparison of the various quarters of the year in a population of 360,138 The total mortality during the winter quarters of the year amounts, according to this table, to 5551, while that of the two milder quarters is 5107, shewing a difference in favour of the warmer portion of the year of 444-the total mortality during the year being 10,746. That this mortality was not greater during the last quarter, when the temperature remained protractedly depressed, was undoubtedly due, in some measure, to the improved condition of the poorer classes in regard to food-that most natural and powerful bulwark against the attacks of disease. Notwithstanding, however, the circumstance that it is possible to account for the excess of mortality in one portion of the present year over another by natural causes, there is an excess of deaths in this city over most other towns, for which some other origin must be sought. The forbidding aspect of a large portion of the dwellings in the older parts of the town, engendering, as they do, an absence of due self-respect, followed by low and debasing habits in their inhabitants, is scarcely surpassed, in regard to extent, in any other British city. Unfortunately, the application of proper sanatory measures, by the formation of new, well-ventilated streets and houses, instead of the condensed habitations at present existing, has been confined to the great Metropolis, and will be employed as another argument in favour of centralisation, unless our local authorities are speedily prepared to devise and apply the adequate remedy. Another desideratum among those classes most liable to disease, is a plentiful supply of the purest water which can be obtained for domestic use, free from sewerage : the connection between impurity of water and mortality, having been well illustrated in the condition of London. Again, it becomes a question of import to health, if the noble Clyde, with its sewerlike waters and impure exhalations, be not equally conveying, in its present state of pollution, wealth and malady to a teeming city. And lastly, the fearful mortality from smallpox and other endemics, urgently demands that the Scottish population should be placed on an equality with that of England, by an extension to our kingdom of the Vaccination Act, as well as of the Registration Act, which, if committed to the excellent administration of the RegistrarGeneral of England, could be brought into operation, with the machinery at present in existence, with but a trifling addition to the expense of the country. Scotland would thus be removed from the unenviable position of being classed with Spain, Greece, Hungary, Turkey, and Ireland, as the only parts of the civilised States in Europe where authentic official registers are not kept. NOTE. The blanks in the preceding Tables are due to the circumstance that the new form of Mortality Bill was introduced only in April. On Fossil Footprints. By ROBERT HARKNESS, Esq. Since the commencement of the present century science has made such rapid advancement that it in a great measure possesses a new and a different character. Some of its branches have so far influenced the progress of society that our present position results almost entirely from their application to the common businesses of life; and others may be |