GARDEN IRRIGATION ITS ADVANTAGES AND LIMITS. 35 



The rainfall at Boston, as observed by the Superintendent of 

 Sewers, for the past six years, for the five growing months above 

 named, varies from a maximum of 10^ inches in the month of 

 August, 1872, to a minimum of 0.65 inch in June, 1873. During 

 these six 3'ears there was not a single year when we did not suffer 

 more or less from drought during some portion of the summer. 

 Twenty-one of the thirty months in question had less rainfall than 

 six inches per month, and the average of these twent3'-one months 

 was but 3.02 inches per month, or only about half what was 

 needed for a full crop of garden products. Some of the protracted 

 seasons of drought were almost entirely rainless for six weeks, 

 during which the weather was excessively hot and wind}', and vege- 

 tation suffered extremely in consequence. 



2d. The Sources of Supply. Many gardens are so situated as to 

 be able to draw upon the public water-works for a supply. The 

 gardeners of Arlington and Winchester, and many other towns, 

 have found this a very convenient and profitable method of water- 

 ing their gardens, and in general where the water rates are not ex- 

 cessivel}^ high, and where the gardener has not at hand a cheap, 

 natural source of water, the public works will be found both con- 

 venient and reliable. There are, however, many farms and gardens 

 beyond the reach of the public water- works, where private works 

 might profitably be erected for iirigation. As above noticed, how- 

 ever, the amount of water required for any satisfactory- result is 

 very large, and before embarking in an}' enterprise of this kind, it 

 would be best to make sure that the source can be depended upon 

 for a sufficient supply- in the driest seasons; for it is precisel}^ at 

 such times that most water is needed. 



Springs and wells are entirely inadequate to furnish water for 

 anything more than a small patch of garden. The only sources to 

 be depended upon for any considerable amount of irrigation, will be 

 found in rivers, lakes, and ponds. There are few gardens so favor- 

 ably situated that the water can be drawn b}^ canals or ditches 

 directly from some pond or stream to irrigate the surface. Where 

 this can be done, it is by far the cheapest method, and it is in this 

 way that the extensive irrigating works of Lombardy, Spain, 

 France, California, and Colorado are constructed. 



Where this system is adopted, considerable expense will be re- 

 quired to grade the land into beds or levels, so as to distribute the 

 water easily and evenly ; but once done, the water is afterwards 



