Efficiency of Turbines.

In reporting the efficiency of the many water wheels brought to be tested dur ing the past ten years, it has been a very difficult matter to suit all that have been interested, yet no builder has ever expressed a dubt that any other builder has ever received a less favorable report than he descrved; but in their own particular case something a little more favorable should have been said, or something unfavorable left unsaid. Thousands have asked my advice in turbine matters, and many hundreds, if not thousands of turbines have been selected upon the advice given; yet not a single complaint has ever been made that the wheel recommended proved unworthy of the recommendation, nor in the ten years, has a wheel that I have reported poor, proved by practical use to be good. Time will determine whether my opinions, statements and reports relative to turbine matters have been well founded, and to that decision I am willing to trust.

In making up the following reports, my purpose has been more to aid builders in selecting the best plans than to sell wheels constructed upon any of those now existing; to do so, requires a knowledge of the lowest as well as of the highest results obtained by test of each, and such are given.

The extreme variations in the results obtained from every kind tested, should convince purchasers that there is no certain way of procuring a good turbine otherwise than by testing, before acceptance, as they would do if purchasing a horse.

The wheel of B. J. Barber might properly have been placed in the group with the Wynkoop and others of that class-not that Mr. Barber believed in perpetual motion or 175 per cent. wheels; but he believed that an unexpended force remained in the water discharged by any single turbine, and that that force could be utilized by adding a second wheel below the first. His plan, however, carried out as shown, simply produces the ordinary downward discharge wheel. Mr. Barber erred in using the central discharge at all for much better results are possible with the plain downward discharge than can be obtained from the central, or his combination.

The other wheels with double discharge, reported in the following pages, such as the Swain, Leffel, Eclipse, Angell, Walsh and others, were so constructed, under the expectation of obtaining increased capacity for a given diameter, but a comparison with the capacity of recent plans will show that such expectations were not well founded.

A. M. Swain, North Chelmsford, Mass.

SWAIN TURBINE.

One of the earlier high class wheels, made with many buckets and small openings, placed in "quarter turn" or "flume curb." Mr. Swain had much to do about starting the testing system. Quite a number of these wheels, ranging in size from 18 to 42 inches in diameter have been tested.

The Boyden turbine is highly recommended by its builder, and is much admired by the corporation superintendent, in kids, whose responsibility is remote; but the practical manufacturer, who has his own bills to pay, lets it severely alone. As may be seen by the diagrams, wheels constructed upon any of the popular plans represented in this work, may be made far superior in every respect, at one half its cost. Its continued use is owing solely to the low state of intelligence in milling engineering. It is idle to expect perfection or any constant efficiency in turbines until purchasers become sufficiently awake to their own interests to be willing to pay a fair price, and then to insist upon knowing exactly what the very wheel that is to be purchased will do before accepting it. The same quality of workmanship will make any other kind of turbine as durable as the Boyden.

Boyden Turbine.

In the purchase of this turbine, more ignorance is displayed than a well-wisher of his race likes to acknowledge lies dormant in the average business man of the times; in purchasing any other kind of turbine the purchaser almost inva riably makes inquiries in order to get the best; the Boyden seeker makes no inquiries except, perhaps, as to capacity and cost, supposing all to be alike as to efficiency, whether made by an expert mechanic or the veriest botch. There is no reason to doubt but what at whole gate an outward discharge wheel may be male to give a high useful effect, but every intelligent turbine builder knows that of all wheels the outward discharge is the most difficult to get just right; also, that good part gate results are impossible with such discharge. There are vague rumors of remarkable results obtained by Mr. Boyden, as there are of the Humphrey and every other turbine, but such results are rarely confirmed when the wheels are tested by competent disinterested engineers. Of four Boyden wheels tested in a Connecticut mill, three were found to be giving 46 per cent. useful effect, the fourth gave 47. At Unionville, Conn., Platner & Porter Mf'g Co., a test of one gave 61 per cent. The wheel was built by the Ames Mfg Co., of Chicopee, and is named in a recent circular of that Company in commen dation of that style of turbine. A nice brass bucket wheel, made by the same Company in 1871, 72 inches in diameter, 51 openings, each 7.26 inches in height, 11⁄2 inches in width, rated to discharge 6360 cubic feet of water under 24 feet head, at 98 revolutions per minute, and to give 217 horse power, was tested at the Dwight No. 7 mill, Chicopee, Mass., Nov. 6, 1878. The tests at its geared speed are given below: