Nor was he content without trying to ameliorate the temporal condition of his parishioners.  By the care of his own garden he sought to teach them more intelligent and productive methods of agriculture than the rude processes to which they were accustomed.  In the valley of Fressiniere he built an aqueduct for purposes of irrigation, overcoming prejudice and opposition by beginning the work with his own hands.  The example of Oberlin was constantly before him, and he often expresses his ambition to be to his people such a guide and helper as the pastor of Ban de la Roche had been to the peasants of the Vosges.

Neff was not long in discovering that his work must begin with the most elementary instruction.  Generally, the people were ignorant of any language but their native patois.  Up to this period their schoolmasters, paid at the rate of twenty-five francs a year, had been peasants like themselves.  Their only time for study was such of the year as was not needed for the tilling of the niggardly soil or spent in the care of the flocks.  And even the little they were able to learn was easily lost on account of the scarcity of books.  Neff first addressed himself to learning the patois, and then, as he went from village to village, made ordinary teaching a part of his pastoral functions.  At the beginning of his second winter he resolved to undertake the training of teachers.  “I foresaw,” he writes, “that the truth which I had been permitted to preach would not only not spread, but might even be lost, unless something should be done to promote its continuance.”  Accordingly, for five months he relinquished the more congenial general work of his parish and devoted himself to a normal school at Dourmillouse.  One reason for planting it there was the inaccessibility of the place and its consequent freedom from distraction.  More than twenty young men from other villages cheerfully submitted to the long confinement in this ice-bound fastness, and the people of Dourmillouse were glad to make room in their huts for the new-comers, and to add to the supplies brought by them their own scanty stores.

The following winter, his third in the High Alps, Neff again opened this school, dividing its care, however, with one of his most capable pupils of the previous year, and paying occasional visits to other parts of his parish.  But now his health, never robust, began to give way under the incessant strain to which it was subjected.  Early in the spring of 1829 he was forced to go to Geneva with the hope of recruiting.  There, after two years of suffering, the details of which are painful beyond expression, he died at the age of thirty-one.